a) One of its screws WD3200BJKT took a long time, quiet, reliable. Modern it's hard to tell exactly.
b) Screws only with the acceleration sensors/fall/blow to take, without them — the killing, though they are usually +20% more expensive, but this is the case when a toad should suffocate.
C) the Difference between 7200 and 5400 other things being equal , significantly. But "other things being equal" is rare, so it is necessary to look tests of specific models before buying. For example in one line WD different speeds very will know, but compare different years models from different manufacturers is useless.
g) 16Mb cache significantly better, but 8Mb is not depressing. To pay for 16 — makes sense, but after him if not a suitable model — it makes no sense.
d) Into the laptop it makes sense to take the SSD, they are certainly more expensive, but the price difference between the laptop and the SSD screw is much less than between the desktop and the SSD screws. But the difference in speed inspire + incredible resistance to shock/vibration.
e) In the case of taking the SSD into the laptop, nice to have "somewhere near" screw for bakarov, SSD rarely, but sometimes suddenly die.