I've looked at several brands of "C"s recently. To protect the innocent/guilty, I'm not naming the ones I found fault with:
One brand was decent. The model I wanted had a number of rough edges that I could deal with (replace the battery converter, add a resonator to the Onan, etc.) The price was nice. The rig's manual? A slapdash of warnings. I've also read about a number of gripes about other issues.
Another brand just had sloppy fit/finish, even though they had some innovative floor plans. Checked roof? Yep, rubber... which means that it is leaking or it will leak. Looked at details, the seams were at places where water would be hitting it at 70+ mph on the road during a storm. If I replaced the fans with Fantastic Fans, added Maxx-Air (or similar) covers, added venturi vents, and then had a place like rvroof.com or Rhino Linings spray the entire roof with an elastomeric epoxy coating... it would be OK. However, without that, it wasn't that acceptable. To boot, the OCCC was puny.
Another brand promised a fiberglass roof. Went up the ladder to look at something else... the roof was really rubber, and it looked like it would pool water unless I parked the rig so un-level that the fridge would cook itself. Nothing like the disclaimer about things changing without notice.
There was one manufacturer that didn't have anything in the size range I was looking for (I'd like to get something under 24-25 feet with a slide-out), but their build quality was excellent, their manuals extremely well written, plumbing and electrical well diagrammed, and with fiberglass roofs. I just wish they had an E-450 with a V-10 in a form factor under 26 feet.
Finally, there is one direct maker which does a great job (E-450 on a 24 footer, with a decent slide-out), and can have customizations like a 50 amp circuit with two air conditioners with heat strips, and even possibly up-rate the towing capacity on the model past the usual 5000 pounds. However, I worry about warranty service, and where I live, if you don't buy from a local dealer, you are hosed when it comes to that, so even though the direct place makes top tier stuff, I'd rather buy from a local dealer.