I never had the N900 last for more than a day with GSM off, wifi on, skype and some voip stuff on. My Samsung will last for 2 days of standby AND moderate use. Granted, it has a bigger battery and a more efficient processor, but I think that's more to it than just hardware.

Talking about the OS without talking of hardware is meaningless. I think you can put Android on N900 (not sure how well it works, and if it is usable). You can't put Meego on the Samsung.

Anyway, I was comparing it with the N900. The N9 is closer in hardware specs, and I would not buy a N9, even if it were at the same price. What matters most is the software. You just can't get the software selection and ease of use on Maemo/Meego. Installing most of the stuff requires hacks, some minor some not so minor.