The life span of the batteries in the announced laptops are rather good - in excess of 90 mins for most cases, so they "the life span is pretty dire for chips better than the SA" is bumpkin.
If you remove the WinXP crap from the laptop and run a Linux distro of your choice on there with WineX and VA, they are extremely good value. My current laptop has a Celeron 1.2 on, I get an hour out of the battery and frankly, it's not very good, but is a hell of a lot better since moving to the 2.6.0 kernel. I've used the machines as is and with XP, the machines really fly with VA and OS 4/Select on. The testing with WineX and VA is even faster.
Note : Virtual Acorn have said in an email to me that they are unable to support VARPC under Linux currently, but that they have reproduced an article on their website which is soon to be updated for WineX.
Of course, it goes without saying that it would be nicer to have a real RISC OS laptop, but for the moment, this is what we have.