Yes, I'm clearly going to recommend the JVC if it is within budget. The jump in contrast, in a good theater space, is really incredible. At the end of the day, I've seen the better Epson models, and the entry level DLP models. I've seen the Sony 40ES... And then there is JVC. Looking elsewhere at forums, when you are talking about serious theaters, then the discussion is almost exclusively JVC, and it has been that way for a number of years, and it has been that way for a reason.
Contrast, black level, shadow detail, color accuracy, motion handling are all more important than resolution. The JVC models are now something like four generations in on their e-shift technology (faux-k) and JVC really has improved with each subsequent generation.
Is having a new receiver and a few new speakers great? Sure! But, in a good theater space with dark paint and proper treatments there is simply no projector that really bests the JVC models. It would certainly be my purchase if I was in the market right now. It is my eventual goal to have one in my theater if I can swing it.
All that said, early reviews of the UHD65 have been a real home run. I just think some serious look at their shadow details and contrast really need to take place before I am on board. Certainly it will require much tighter constraints on placement compared to the JVC or other models in that price range.
If budget really is tight, and there won't be funds coming in for a long time, then waiting, with patience, on the Optoma may be the better choice for you today. It will give you time to see a few more reviews come out and really get a good idea of how it stacks up against the competition and if it is a smart buy. It may very well be, in which case it could reign supreme for a while as the 'best' entry level 4K projector on the market.