Not sure why it would be cheaper to let Apple do the upgrade. What you get for that price is less than what you could do yourself in a snap.
If you want, I could do a small review on daily usage of the coming Vertex 3, which supposedly should be the fastest thing around (atleast until OWC and Crucial spit something new out in a couple of months). I'll be getting it in 2 weeks time, and very much looking forward to it.
The price I'm paying for the Vertex 3 is $65 more than the Apple SSD of the same size (256gb). The speed difference is significantly more...
The advantages? Well... I'm not hardware buff, but I did read a lot before making up my mind.
Depending on what your needs are, you should find out what the specific drive is good at. I absolutely need one that is good at both random and sequential read/writing. That's why I chose Vertex 3.
If I only needed random writing I would choose something else (cheaper).
Also note the talks around how some drives seem to be causing problems for some machines. I noticed a lot of Intel 510 talk, and that coupled with its extremely inferior speed I chose not to even take an interest in it.
What you'll be getting is speed, less heat and no moving parts... moving parts are bad
What will you be using your computer for?