Leica proposes to upgrade on existing M8s, for $2,150 as of this writing (March 8, 2009), the LCD cover material, the shutter, and the frameline masks.  The question is why anyone should bite down on this.  Forget the usual dismissals to the effect of, "well, if you can't afford it, you have no right to complain," and comments about Leica's making (or not making) a profit on it.  The real reasons to skip the upgrade have nothing to do with socioeconomics, Leica's munificence, or Leica's chiseling its customers; rather, they have to do with the value added to the camera.

The three up- (or side- or down-) grades.

The first question is what upgrades do or do not do for the camera.  First, a synthetic sapphire LCD crystal is a bit absurd.  Is it more scratch resistant than the original plastic?  Unquestionably.  But unlike your watch crystal (good ones are made of the same synthetic sapphire), where there is a reason to use it, a digital camera is not usually in danger of accidentally contacting a door frame, contacting your cufflinks, or otherwise getting scuffed.  Although it is possible that some Leica owners put their cameras in bags with their car keys or wear sharp-edged commemorative metal pins that could scratch the original LCD cover, these concerns can be met with stick-on protective film designed for handhelds and other LCDs.  Or a leather half case.  Or being more attentive.  Synthetic sapphire does not improve impact resistance - so it does not protect against cracked screens, a much bigger problem.  So what makes this attractive to anyone?  That it makes the LCD cover half a millimeter flatter?  That it matches the user's Rolex?

Second, "upgrading" the shutter to be quieter at the cost of a higher top speed and lower synch speed is, in this writer's opinion, a loss.  The original shutter is not that loud (particularly with the firmware upgrade that disassociates firing from recharging).  To lose 1/8000 sec via the upgrade impacts a small amount of selective focus pictures outdoors, but dropping the synch speed to 1/125 sec is very debilitating for daylight fill flash, particularly with the medium-powered SF-24D.  So if the score is that the camera loses capabilities and the shutter is not that much quieter, what drives these upgrades?  A belief that an antique-looking camera is going to suddenly become invisible just because it makes slightly less noise?

Finally, upgrading the framelines in any way that does not provide for field size variations with focused distance is a waste.  Yes, the original M8 framelines grossly underestimate frame coverage everywhere except close-up.  But any M8 framelines on the current model will only be accurate at one distance.  Hence, with the Leica frameline design, upgrade or not, you either (a) must learn to mentally compensate in the finder; (b) check framing by chimping; or (c) learn to crop.  The Leica M series' framelines have been obsolete since the late 1950s, when the Konica IIIA came out with field-compensating, parallax-corrected framelines (well, that was only a couple of years after the Leica M framelines came out...).  And today, one can improve even on those.  Field-compensating LCD framelines adjustable for focal length already exist in the Fuji GA645zi.  Leica can easily adapt such a system, since (i) the RF cam across M-mount lenses is always in the same position for any given distance; (ii) the current frameline system receives distance information from the lens cam - and a multi-position functional resistance element (FRE) could be installed; and (iii) the 6-bit code tells the camera exactly what lens is mounted.  So pending some creativity on Leica's part, the bottom line to the frameline upgrade is to trade one arbitrary and inaccurate frame coverage for another.

Extending amortization

Unless you are writing off a camera as a business expense, the cost of owning a pro-level camera is about $1,000 a year, or $20 a week, plus any scheduled or unscheduled maintenance.  This comes from depreciation driven by the release of new models.  You could approach this cost in one of two ways. 

The first, and most common, would be to sell the camera after a couple of years and buy a new one.  This is actually not a bad thing to do.  There is a large market of penurious pros (and semi-pros), and if you ended up getting two years' use at $20 a week, you come out ahead of renting a camera, even for a month - and you can keep upgrading.  So if you own, say, a Nikon D2x, you buy the camera and accessories for $4,800, you sell it two years later for $2,800, and then you buy a D3 for $4,800. 

If you practice this, there is no way you would ever want to drop $2,000+ into an M8 that is already 2 years old.  There is no guarantee that spending that much would add anything significant to the resale value.

The second way to attack the cost of ownership is to assume that you are going to keep the camera until it it has been "used up."  That means that you just keep assuming a straight-line drawdown of the cost of the camera from the time you buy it until you give it to charity.  For a $5,000 camera, that's more or less five years.  Look at D1x pricing on Ebay, and it's pretty easy to confirm that after 5 years, a digital camera is often worth 10-25% of its original price. 

There is nothing wrong with "using up" a digital camera.  The emergence of a new camera model does not make the old one stop taking pictures.  But the danger with the "using up" model of use is that the cost of a non-warranty mechanical failure (or accidental sensor damage) becomes higher and higher relative to the cost of buying a new camera.  Labor costs do not go down over time.  So from an economic standpoint, you might never reach the intended lifespan, and it's unlikely that anyone would replace a 4- or 5-year old digital camera with the same model.   Note also that although some makers are better than others, the chances of getting parts for anything more than 10 years after the discontinuance of production can be very problematic.

Dropping $2,000 +in upgrades into a camera would seem to either increase the amount of time you have to keep it or worsen the "total loss" that would occur if the camera failed late (but not all the way) through the intended period of keeping it.

Although I am sure someone will protest that "Leicas last forever," the M8 series incorporates perishable parts that are not in the old, tank-like Leica bodies.  They have motorized shutters whose capacitors can go bad, an LCD frame counter that might start leaking (anyone remember the Nikon F3?), a color LCD backlight that has a finite life in hours, and lithium-ion batteries that lose the ability to charge after a few hundred uses.  So the assumption must be "some maintenance," and as noted above, that must be measured against the value of the camera and its capabilities in the future.

And what does this have to do with the price of tee in Solms?

At the end of the day, though, the problem is not the upgrades themselves or that they would compel you to keep the camera longer than you ordinarily would.  The simplest reason to skip the upgrades comes from comparing what the upgrades cost and whether they add any meaningful capability that is worth 2/3 the price of a used stock M8 in today's market.

Two-thousand-plus for an upgraded sensor (higher resolution, higher DR, whatever) would be one thing, but Leica is offering an amazingly expensive upgrade that does not add real operational value to the camera.  Maybe psychological value, but that's not going to matter when your camera is on Ebay.  In fact, if you wanted the M8.2's features, all you would have to do is wait 3 years, and you could buy a used M8.2 for about the price of the M8 upgrade

My own personal decision would hinge on  the fact that my capabilities would be much more greatly augmented by keeping my M8 as is, saving the $2,150, adding it to another $2,000 and buying a Nikon D3.  Looking at the pictures from my wedding, shot on a D3, many at ISO 4000, was enough to tell me that unless Leica (allegedly a "low light" camera) can deliver performance on that level, it's not worth rearranging the deck chairs on the Hindenburg.