I will look this one up as well I am not familiar with it either
The JVC 250 is way too dim for your screen size and throw distance. And please DO NOT buy a projector based on some You Tube videos. If you cannot see a projector in person, all you can do is go by the reviews at Projectorcentral.com and Projectorreviews.com(Art does the best, most thorough reviews out there). And of course customer reviews here and at Avsforum(but beware most projector owners think their projector is the best, that's why they bought it).
The Vivitek 5080 got a very good review at Projectorreviews.com, but it's right on the edge of brightness for you. With your throw distance of 14.5' and 120" diagonal screen, it shows 16 foot lamberts(16 is the desired minimum). So when the bulb dims a little, you will have to run the bulb on high power mode. And that cuts bulb hours down to 2000 hours, instead of 3000. And in Art's review, he lists the 5080's noise level as one of it's cons. There's nothing worse than sitting near a noisy projector.