I love the tones of this amp combined with my GLP!
Long Story Short: Over the course of a year-and-a-half I went from a Vox VT40+ to a Peavey Vypyr 75 to this VT80+. And I'm very glad I did!
The VT80+ has a LOT more bottom end than the VT40+...enough to compete with any other amp I've ever played through. While the VT40+ has a higher high end, the VT80+ comes surprisingly close. The cleans are better than the Vypyr series, and the overdrive definitely feels more organic. In my opinion, the Vypyr series are geared more toward Metal / Death Metal bands while providing some other options, and the VT+ series is geared more for the Classic Rocker / Blues Players. That's not to say that the VT+ can't do Metal: it can, most definitely! And it doesn't sound near as raw as the Vypyrs.
Peavey, though, and two advantages over this series: 1) the interface is easier to use (some features on the VT+ series are not so obvious); and 2) it allows you to store more of your own presets (12 versus the 8 on the Vox). You really want to sit down and go through the manual on this amp before you start playing...otherwise you might feel as if you're missing something. Also, make sure you understand the difference of when you're in Preset Mode and Manual Mode.
And be sure to play around with the Power Attenuator...sometimes just moving it a fraction of an inch can drastically change your tone. One of the great advantages of this modeling amp having a tube in it!