Adding a SSD is like when Vin Diesel hits the NOS button in the movie with Paul Walker and Shiloh Buff.
One minute you are going, next minute the road markings turns to bars, life slows down ten fold and occurs in slow motion, and then Harrison Ford is next you screaming TERMINAL VELOCITY (or in some cases 'get off my plane'). You get my imagery.
You will wonder how you lived without one. Buy a SSD now. It's worth the money and you will appreciate it every day. I know a lot of people with the Intel 25 and not one has had an issue; it is a solid and proven design, but compared to the offerings by Crucial, Vertex, OWC and a few others, it is the same (or more) in price but slightly dated hence Intel is introducing a replacement for it.
I have the OWC Mercury Extreme Pro 120 (technically it is 128gb but there are 8gb of crap that the drive uses to make it happy and long lasting). I love everything about it and I would have bought it if it was priced twice as much as it is. I was going to go with Intel until I saw a benchmark comparison, pro reviews, and many user ratings, and then went with the OWC due to a pretty significant differences and supposedly better block management and wear leveling (although I don't know enough about how the management works to say if it is true or not but I'll take OWC's advice as they are good folks). Either way, the OWC has the best user reviews of any current SSD. With that said, OWC is very specialized and the people purchasing OWC products are computer people where as you can get other certain SSD's in stores. It could be argued that the other SSD's do not have as good of user reviews because most people are idiots. Also, the support for installing OWC products is second to none meaning you have fewer people doing the 'pissed off user reviews' because of they get Ikea-like directions. None-the-less the Mercury Extreme Pro is very, very nice and you can't go wrong. Hell, it's EXTREME; and who doesn't like extreme?
