I've got one of these machines (acer aspire 1700) and it is a very nice machine. No Linux yet though it promised.
7.5 Kg is a little heavy though and 1.2 hours battery life with VRPC running isn't great either.
It's definitely a desktop replacement machine rather than a laptop. A Desktop PC and 17 inch screen crammed into a laptop case that has bulged so everything will fit! Including a fullsize, but laptop layout, keyboard and keypad,
Having desktop standard memory, harddrive and processor is some compensation for the weight as it will make upgrading a doddle. Having had 3 harddiscs fail in one PC one after the other I expect to have to replace it every year or so. No fails at all on a RISC PC in twice the time!