I answered this in another thread about a month ago, but here is a quick synopsis.

Comfort Suites: Generally fairly new and fairly consistent. No amenities, but not half-bad.

Comfort Inns: Could be OK, might be scary. More than likely OK for a night or 2.

Quality: Generally pretty crappy, although there are exceptions.

Sleep: Small and boring, but fairly new. Showers are big.

Clarion: Could be fairly nice (PDX) or could be a circa-1950's Marriott that became a Holiday Inn and then a Clarion. If the property is over 10 years old, it's probably a dump. There are some fairly major exceptions.

Cambria: Looks good, but haven't tried it yet.

EconoLodge/Rodeway: I would sooner sleep in my rental car.