We've been pulling our 2004 Vibe (can’t be pulled 4 down) with a Demco KarKaddy SS since we got our 1998 30' Itasca with a 99 Ford V-8 (now 10 years). I like my Vibe so well that I didn't want to & couldn't afford to replace it. A dolly is not as big of a problem as some say on this forum and we've been well pleased with it. I can load it by myself in less than 10 minutes and unload in less than 5 minutes. If strapped down correctly you'll never have a problem with the straps coming loose. It tracks the MH perfectly so you’ll never know it’s back there but you can't back up any better with it than you can 4 down. We’ve never had a problem storing the dolly at a CG and never had additional charges. At home the SS tongue folds back and the ramps fold up to reduce its storage space almost 50%. As said by others above it’s a little messier strapping down in bad weather or in the mud but a piece of plastic to put you knees on helps.
All that said, it is according to how old you are and how good or bad your legs are. I’m going on 76 and it’s getting harder to get down then back up to hook up so I know 4 down may be better for me in the future but I still love my Vibe.
Dave