We went from a low end Keystone product to our 2014 Arctic Fox 29-5T. I view the higher price Keystone products to be simply outfitted with higher end faucets, sinks, carpet, etc. The frame, walls, insulation, etc. varies very little from the unit we traded.
Although our new Arctic Fox had a few minor items needing attention, it certainly has the feel of a well built coach. The weight of the unit is directly related to frame, plywood floor, etc. Keep in mind the carrying capacity before one reaches the GVWR, Northwood products tend to allow one to carry more personal items before one reaches that important number.
The 27-5 will feel small, so don't let it persuade you one way or the other. We also looked at an Excel, but couldn't justify the extra $15000 to $20000 cost (probably better built though, more comfortable furniture, etc.). Also, Northwoods will let you customize your unit to some extent, if you order one yet to be built (not just options, but minor other items too) Arctic Fox units now have many standard items, such as LED lights inside and out, convection microwave.
We can't speak towards long term use, but few used units show up on searches.