I am digging the Stealth!
Comparing with my 5150 III 100 side by side, there is a big difference. Enough so I am keeping both. Reading all these comments I thought I would share my thoughts for... I guess anyone that's going to snatch up one of the last few floating out there or from someone flipping a new one. (By the way there are around 520 made right now worldwide)
First of all , I had a chance to try mine out before buying it, brought my own guitar but played through a stores v30 4x12 rear loaded (not a EVH cab). I have not played through a EVH cab in years but I know I didn't like it when I did. Having currently (15) 4x12 cabs, I have already matched it up to a winner, my mid 70's 25w blackback Marshall straight cab.
The first thing I noticed playing against by 5150 III 100 is the amp is extremely HOT! Like every channels is boosted. I found the mid control can help shape the attack if desired by backing off from 12:00 setting.
Clean Channel: As everyone else mentioned the Clean channel at first felt way too hot breaking up on 3 easily, but I have found no harm running the gain on "1", with no tone loss as you would normally experience on a tube amp at this setting. The cleans are really good and pretty comparable to my ears to the original with the gain at different settings of course.
Blue Channel: the biggest difference in the two amps, the original blue would make a great "channel 2" if this was a 4 channel amp like a Diezel VH4. Just tons of gain and again very HOT. I expected this channel to more compressed than it is, but it's pretty open and raw.
Red Channel: I really like the RED channel, more than others I think. It compares pretty close to the original but hotter.
I know it's not, but I keep thinking that the Stealth was inspired to help compensate for the EVH cabs that are a bit dull to my ears. Even if you go to Celestions website and listen to the sound bite comparisons, the EVH speakers don't sound that great against the other. I bet the stealth works well with it.
Overall, its a cool amp. Somewhat unnecessary as the original is so great, but channel 2 and 3 are hard not to like when you play them side by side. If I had to keep only one it would be the Stealth in a heartbeat with the addition of resonance controls and being I can trim back the gain channels if desired and mimic the original pretty close, but still have more on tap! I have to say the effects loop is just as good as the original which I think is one of the better loops on any high gain amp.
I also had the chance to play the 50w version at the store I bought from and a/b with the Stealth and that was the end of my interest in the 50w version. IMO, There is a major difference in those two, and the 50w sounded really, really thin. It was small and cute and sounded that way too. Bummer because I wanted to have all versions.
...I'll have to cry "ok" and say it'll be 6 months, tops, before we start looking around again 
