The sounds are actually quite good for a built in model. The sound does vary a lot depending on the amp model you're on. I don't think that is based on reality. But it does mean you can get a wide range of sounds just from one effect setting. Somewhere in all that lot, you'll get the sound you want. Some amp models do sound very strange on some settings. The amp isn't noisy but once again, it depends on what amp model you're on. The closest amp setting to a totally clean monitoring setting is the AC15. The gain seems to have to be on a little bit on them all, which is a pain. This makes getting a clean sound on most of the amp models a non-starter.
But if you find a pre-set you like, clean or heavy, you have the facility to be able to read the settings which is good.
Without doubt, this amp is meant to be used as an effects amp and not as a manual amp. But that's fairly obvious because you buy it with all those effects. I think they could have made the manual side of it a bit better.
Two problems I've read about and which I've experienced are not major although one can cause a fright. The guitar input jack comes loose and slides into the amp. This is a known fault so keep your nut tight on that jack.
The other is it's digital brain. It sometimes muddys the sound. A quick flick of a knob corrects this but you can tell it sometimes gets lost a bit. Others have had this quirk.
Other than that, it works well.
A good 8 because the sounds, which is what you buy it for, are quite good. Nothing beats a good pedal but you can get good sounds. You can get all you want, with not too much hassle. The presets are actually quite good too, which is a first.
I'd buy the ad30vt if I was buying again. This is just big without being a 100watts, so no real point.