i'll be buying soon and have also been wondering about the stock SSDs.
from reading, it seems some of the main pros and cons are: (spoken roughly, from a non-expert)
Pros:
only SSDs to have TRIM support on OS X (for now); (though, better SSDs have their own 'trash management' and don't necessarily need it!)
stability; i'm sure plenty of other SSDs run just fine, as so many use them, but apparently there are problems out there
convenience; no fuss!
cost; ... well, assuming you get a high end 15 or 17; in that case its only $100 more to get a 128GB SSD
Cons:
performance; relative performance is unremarkable. also, apparently, much faster SSDs are just around the corner!
life; other SSDs, like OWC(?), promise little to no performance degradation; i think this includes, if not is limited to, the 'trash collection' issue, so maybe TRIM, which is new to OSX?, will help the stock SSDs stay healthier longer;
... it should be noted that, as far as trash collection/performance degradation goes, one solution is to periodically wipe the drive and start fresh; you have to do this in a particular way, but it doesn't seem hard, just inconvenient.
... if i missed anything, or misspoke, im sure MR will rectify!
Aside from BareFeats, check out the AnandTech review. There's a section on SSDs and recommendations. It was enough for me to decide the stock SSD was probably for me. I want stability and was said above, even if its relatively slow, its still an SSD, which is FAST!
http://www.anandtech.com/show/4205/the-macbook-pro-review-13-and-15-inch-2011-brings-sandy-bridge
g
d luck!
