I've had my Salsa Casseroll SS for several months now and can't say enough good things about it. The build is great and I use it for commuting 20+ miles and it doesn't miss a beat when I take it on long limestone/gravel adventures. In fact, I know a guy that rode his Casseroll SS for Dirty Kanza, 200+ miles of gravel in Kansas in a single day.

I wanted to try riding fixed gear and ordered the parts necessary to convert my Casseroll when I decided to test ride a Surly Steamroller at my LBS. It was different enough and I liked the more track like geometry with the higher bottom bracket that I decided to get the Steamroller for my fixie and keep the Casseroll setup for SS. Glad I did as I've ridden the heck out of both bikes in the week since I picked up the Steamroller (~150 miles) and love being able to quickly choose between both bikes without making any changes.

I highly endorse both but the Casseroll is what I would choose at this point if I could only have one or the other.