Welcome to the forum, T-MU !!!
Well, here's some differences between the UV and the RG...
For one, the UV has a single coil between it's humbuckers. Some people really enjoy having a single coil there... but honestly, i like the sound of a split humbucker just as much. And a single coil just gets in the way of my picking. Plus, i think the H-H configuration just looks better than the H-S-H. The RG7's have coil-split humbuckers in positions 2 and 4 of the switch.
The neck profiles are slightly different; the RG7 has an amazingly thin neck!!! I think it's great. Very flat
fretboard radius, too. The UV has a slightly thicker neck profile with a very flat radius; to me, the UV has a more comfortable neck. But this may be because i'm used to playing on the 7-strings that i own, which all have a slightly thick neck.
The UV, no matter what model, will have better stock pickups than any RG7!
The UV guitars just have more character, if you ask me... there's just something magical about them, i can't explain it. In the looks, and in the feel, they just feel more special!
.... however, nothing is more special than a guitar that you've customized! And it just so happens that the RG7 is an excellent platform for customization!!! I'd actually feel bad about modding a UV.
I guess my conclusion is this... you could buy a UV, and be set. It will be amazing from the first time you open the case. Or, you could save a lot of money, buy an RG7, use the extra money for some mods { or at least some new pickups }, and have a guitar that's made exactly how you want it. I guess you could say that you could be happy with someone else's ax { the UV, which a lot of people own }, or be just as happy with something that you modified into something noone else has { a customized RG7 }.
I guess i should let it be known that i plan on owning both of these guitars someday, and that if i had the money, i don't know which i would get first...
I hope this offerred some insight!
Ben