Bill & Karen,
How tall are you? 16' specs: interior height 5'10''. 17' interior height 6'1-1/2". I'm 6' and would never consider anything with a shorter headroom than me. Years ago I looked at a short ceiling RV and got a crick in my neck from just the few minutes I was inside. That made up my mind then that if I ever bought anything I was going to be able to stand up like a homo sapien and not have to make like an ape. Recently, in Yosemite, I met a new (to him) 16' Casita owner and on seeing mine he said was going to sell his and get a 17' model so that he could stand up straight when inside. It could be the difference between loving and hating what you own.
we just short folk and that is why I didn't mention height, I could fit in either but my wife loves big refrigerators and hates bugs so that is why the 16' would have been out for us