THE BEST SOLID STATE AMP IN ITS PRICE RANGE
I've owned two of these amplifiers before, this is my second one. This amp has the best quality and performance in its price range. Before going into detail let me just say that I've been playing for over 10 years and have been through many guitars and amps, so if that adds any merit to what I have to say about this amp please take it at face value at least. The guitar that I currently run through this amp is a Gibson Les Paul studio with humbucker pickups.
The EQ knobs are highly responsive and can be dialed in for any tone you desire. The 3-way voicing switch changes the tone considerably, the Stack setting boosts the Mid frequencies considerably, the Vintage setting boosts both the Mid and High frequencies but lacks in Bass, regardless of how high you have the bass knob set to. The middle position (Modern setting) is the best one to use, it doesn't dampen or boost the effectiveness of any of the knobs like the other settings do, and can be adjusted for any tone you like, whether it be fat low ends or ice picky high's. The mids work best in this setting as well, you can cut them completely or boost them for a very loud and piercing sounds that will cut through if you are playing in a band (this amp IS loud enough for band practice, you should use an SM57 to mic it if you play in a larger room or in front of a crowd though.)
Moving on, the distortion channel has a bad reputation on most solid state Peavey amps, I find that it's entirely dependent on what pickups your guitar has, humbuckers work the best to get the most out of it, with the mids cut, and the low and high end boosted, you can get an excellent Metal tone so long as you crank the amp up, the secret to good distortion is not always MORE GAIN, but HIGH VOLUME.
The clean channel on this amp (and most SS Peavey amps) is the holy grail of it. It's the BEST clean sound you can get for the money at this price level, and it handles pedals better than most amps I've ever played. I can't say much more of it, so just try it out yourself.
Aside from that, the headphone preamp is excellent and delivers a very clean sound for silent practice, just be sure to use a good high end pair of headphones. I can't speak for the Direct Out jack as I've never used it, but I know it can be plugged into a mixing table for recording or playing directly through a PA. The only thing I dislike about this amp is that it does not have a jack for a footswitch, to counter this I run the amp on the clean channel at all times and when I need distortion I just engage my RAT pedal on the floor.