They are faster in read speeds, they can be very, very slow in terms of write speeds, especially the MLC models. I don't think anyone here has ever conclusively determined whether Apple is using MLC or SLC (the faster variety), but I suspect they are using high end MLC models (otherwise, the cost would be incredible for a 256GB model). Again, the drives are maturing rapidly, but they still haven't hit the sweet spot for price/performance in my view. Yes, they will generate less heat and take less power, but I wouldn't let that be a selling point because I think the heat output of modern drives is pretty intangible, especially with the MBP's aluminum case acting as a heat sink.
If you're rendering 3D graphics and it's critical that something needs to render in 30 seconds as opposed to a minute, then yes. But for most consumers and in general computing, the difference would likely be indiscernible. We're talking about 270MHz mind you.
Really? You should be able to get an educator's discount.
The drive is considered user-replaceable and Apple provides instructions for doing so. It's as easy as removing a few screws, then the bottom of the case is released and you can access the drive (and the battery too for that matter, although Apple wants you to pay them for the honor of doing that).
