I've used them before, and had another good experience. Rate was excellent. Showed up, and was quickly seen by the next agent (who was at the Thrifty counter). After a mild upsell attempt, we got our base-model Toyota Yaris (21,000 miles). Drove it up out of PHX in record 117-degree heat with no issues, and around Flagstaff/Sedona for a week. Dropped it off without issue. Two notes:
-For two people, a Yaris hatchback with the rear seats folded down will have as much or more space than a small-ish sedan. We used about one tank of gas all week in the Yaris.
-There's no rule you can't go out to the car lot and see what's out there before getting in line. That way if they threaten you with the dreaded Chevy Sonic, you can see if there actually any out there beforehand.
People really seem to bash Firefly, but so far I haven't had issues.