UHF is a silly, good-natured comedy. While it is clearly a product of its time, the humor is timeless. Lots of slapstick, parodies, and quotable lines. It's Weird Al's humor, but it targets a broad enough audience- think Airplane/Naked Gun comedy, but it doesn't go over the top. Even though Weird Al is the lead, he yields plenty of screen time to the excellent supporting cast.
As for the 25th anniversary blu-ray edition, the picture quality is improved from DVD (obvious to notice from the special feature DVD picture quality), but the original film quality wasn't that sharp to begin with. I had it on VHS; it looked blurry then, so anything is an improvement. The special features from the original DVD are retained, but the only additional feature on blu-ray is Al's 2014 Comic Con panel, a single-camera 50 minute interview and Q & A.
So if you're looking to upgrade from the DVD, you only get the improved picture and the Comic Con piece. If you've never seen UHF, it's a must-see and must-own. So don't be "STUPID!"