In my personal experience, I wouldn't recommend either TV. I did a part time job selling TV's at Sears so I'm no professional but I know more than most people about the topic. I would look to go plasma or LCD. The biggest default to projection TV's is their viewing angle is so much less than a plasma or LCD. Yes you may be able to see the picture but its darker and less clear. Projection TV's cost less per square inch but you can still buy a good plasma or LCD (40-42") for the same as a 50-60" projection. There is a whole laundry list of why plasma and LCD beat projection in almost every catagory but price. But personally a 42" or 50" TV is still going to look sweet. LCD's and plasma do come in 46" and larger but after the 40-42" size the price really goes up.
As far as the 1080P goes, I would hold off. Unless you got the money to burn the human eye can hardly detect the difference. Blue ray players and PS3's (built in blue ray) are the only thing that can play 1080p and if your not going to get one, your basically spending money on technology that 1) basically you can't view until you get a blue ray player & 2) is new and therefore still over priced.
I don't have any experience with the JVC TV, but I have always been a fan of Sony's TV's. In fact Sony is going to be terminating their tube, projection & plasma TV market for the LCD line in the near future to focus on just LCD technology.