I don't have any other Keen shoes, but they seem true-to-length, and on the wide side in width. I ordered my normal size.
Redrhodie, REI is great about returns. You'll be fine.
One thing about the North Face boots -- as Lisa observed, the shaft of the boots is higher than some of the others mentioned here. ***Both the shaft of the boot and the soles are fairly stiff**. Don't know if this would be good, bad or otherwise for snowshoeing, but I thought it was worth mentioning.
When it's really deep and cold I wear Sorel boots.
For snowshoeing, I wear my normal hiking boots with a pair of Neo's over them. http://www.overshoe.com/recreational/ They keep you warm and dry, but you're wearing your normal boots, so the fit is good. When I've tried to wear the Sorels or other heavy boots with the snowshoes, my feet and legs get more tired because they just don't fit like my normal shoes.
Alright I ended up getting the Merrell Winterlude 6 boots in black and I LOVE them!! They were super comfy from the moment I stepped into them. The North Face McCurdo was the other one I was seriously considering but when I tried them on they really felt tight across the top of my foot. I have a super high arch and they were just too snug, even in a larger size. Plus I think I decided that a higher boot bugs me where it hit my leg higher up. I'll just get some gators to ensure no snow invades my warm, snuggly, dry feet through the top of the Merrells! Thanks to everyone for your help and advice!
"For God did not give us a spirit of timidity but a spirit of power, of love and of self discipline." 2 Timothy 1:7