Pros Boot time is under 15 seconds vs the 30+ seconds of a traditional 5400rpm notebook HDD. Programs and applications open faster. It also has a 5 year warranty.
Cons Cost vs a higher capacity hdd, but this is universal for all ssd's.
Summary I purchased one for my early 2011 macbook pro. I got mine on sale for under $200 and it has been worth every penny. My boot up times were cut by more than half since the 5400 rpm hdd is no longer bottlenecking everything. A 256gb pre-configured through apple is $500, and you will wind up with one that the vertex 4 will outperform.
Installing was simple, except that apple uses a t6 screw for the hdd mounts, so I had to run to a hardware store. The drive was immediately recognized, so a quick format and a fresh os install and I was up and running. It is possible to restore from the old hdd, but i'd recommend just backing up whatever files you need and transferring them later. I have heard horror stories about hdd to ssd cloning, so for me it was best to avoid any potential problems.
SSD's are hands down the best upgrade you can put into a notebook, I don't know how I was able to deal with traditional hdd's before. I've never been a huge fan of ssd's in desktops, but if it's powered on and off a lot, it is well worth it.