Wow, thanks for this great thread, it was a question I had also. Our local dealer has a 2014 - 351DSF on the lot, no 2015's yet. They really want to get rid of it of course, but the features all mentioned here are things we weren't sure we liked on the 2014 they have on the floor - the partial carpet and the non-sliding living room TV (I asked them to change that out). I've found online dealerships listing their price as only $3000 difference between the 2014 and 2015.
Decisions, decisions....I would expect I can negotiate more on the 2014, but I'd also rather have what I really want and not settle.