Neither is a particularly great hotel I think, but I've not stayed at either. Tripadvisor is probably your friend here.

The Sandman might have a slight edge for being on 7 ave, and close to the C train. The train is free on the 7 ave strip, so you can use it to get to other restaurants. There are a number on 8 ave, say between 2 st SW and 1 street SE (Teatro's at Olympic Plaza)

I like Thompson's in the Hyatt (nice hotel too) and Murrieta's in the Alberta Hotel building ( 1 st and 8 ave). It's been a while since I've been to Tribune on 8 ave, but they used to be good. If you want to go a bit further, the River Cafe on Prince's Island is excellent. I'm not sure if they are open in the winter though.