i've never really found it to get any hotter then my old tibook 550 did that this machine replaced...
all laptops get hot...
i am running os 10.3.2 and i actually got annoyed with how the fan started coming on earlier, so i installed the silent night patch and now my fan cuts in when it used to, so i am completly happy again.
i seem to think that since installing os 10.3.2 the actual operating temeratures don't rise like they used to on this machine, so i think overall operating temperatures may have dropped??? can't say forsure but to me it does seem like it.
if the heat thing does bother you, just get a podium cool pad, i got one, and it also helps with the angle it puts the machine on , makes for better typing position.
640 max ram is what i have in this maching, the REV A however can accept a 1gig chip, so in theory the REV A can be expanded to almost the same ram specs as it's REV B brother.
i do find myself eyeing up the 15" al books these days as the extra screen space would be a nice thing as this 12" powerbook is currently my only mac at the moment..
I was concidering a rev a until I took a look at the educational discount on the 1ghz rev b. $1999 plus tax, that is $300 off the regular price! Macdoc is selling a rev a at $1770, a rev b for $230 more is a good deal.