I've found it easy enough to text with one hand, but you're correct about mistaken button presses, ending up back at the menu when you've tried just to delete a letter does get a bit annoying after a while
I've seen a lot of griping about the sat nav, but I'm quite happy with it. It's more than fine for occasional use. We got lost heading for darkest MK last week and had it not been for the phone I think the missus would have had us heading for Dorset. Downloading the maps from the Nokia site thru the PC beforehand helped (can't believe how few folks on other forums do this), saving time and money, rather than the N95 going online repeatedly for new maps. Found us a petrol station sharpish too while extremely lost.
On a side note, never again will I undertake a 6 hour car journey with a PMT-ish girlfriend driving