I don't think will regret choosing either one of these manufactures. If you are going to buy either one, get the one that suits you the best. At the price point the units are I think they are similar in materials and build quality
Tiffin has no equal in over the top after sales support. Winnebago gets my vote for engineering design and layout and the documentation (schematics, diagrams) available for Winnebago are excellent. After sales support for Winnebago seems to be more dealer sensitive than Tiffin.
I have never owned either brand... My perspective is based on my experience working on them and the 12 years of moderating this forum. No Holiday Inn insights :).
JohnnyT