Youtube channel FamilyGamerTV has their hands on the New 3DS and they've given it the once-over in this video. In particular they tested to see how the new handheld's battery stacked up against older models. Sadly they didn't have access to the New 3DS XL--you know, the only one America is getting--but the results are still intriguing.
This test was performed with the 3D, Wifi, and brightness cranked all the way up, and with power-saving mode disabled. The dumpy old original 3DS didn't even manage 3 hours of battery life. The 3DS XL and New 3DS managed about an hour better at around 3 and a half hours each. Naturally the 2DS lasted the longest at just over 4 hours, but of course it doesn't have the 3D effect eating up battery.
Still pretty mediocre in my opinion, but battery life has always been the Achilles' heel of the 3DS family. I'll be interested to see how the New 3DS XL fares when it arrives February 13th.