I have installed SSDs in two Thinkpad x60s laptops, one
ls800 tablet, and two 3GHz desktops.
On all of these, there is a huge speedup on all disk read operations - of the order of 3x to 5x. Especially on some programs which load complicated databases. Jepp Flitestar is one example.
There is also a 2x to 3x speedup in booting time.
You also don't need degragmentation so that is one less thing to bother with
Altitude operation is obviously improved. A normal HD crashes reliably around FL130-140 if unpressurised.
Obviously a SSD is far more robust. On laptops which have shock protection for the HD, you can uninstall that bit of software, which stops HD accesses while the thing is being carried around.
Power consumption is also much lower, though not much effect on battery life on laptops due to most of it being due to the backlight. I see maybe a 25% improvement on the Thinkpads or the ls800.
As regards reliability, probably not much in it. I have chucked out a fair number of hard drives over the years, usually losing all data on ones which actually failed (rather than just got noisy). I also chucked away one 128GB SSD the other day, which get very hard to boot up, with a suspected temperature dependence.