This thing is unreal.
I first have to say quiet as can be, for those that might be concerned based on one of the older heads. Not this thing it's just about the quietest thing on the planet.
The flat tone is great and very similar to the Doubler with a little more low end push. To get them almost identical I cut some lows (-10db@55hz approximately).
So this head is ridiculously loud, there will be very few cabinets that this thing cannot fully power. As a point of reference my favorite head a Glock HR which is a monster led sled with 750 watts at 4 ohms and I'd say the IAMP Pro will easily keep up if not beat it out in terms of sheer volume.
I was lucky enough to own an IAMP350 for a good period of time and from a tone shaping angle this thing is just perfect, you can dial in just about anything you can dream up. At the same time the head sounds killer totally flat. I don't love the presets accept contour I sounded pretty nice, otherwise there not my thing, I wouldn't be suprised if other people really love those features though.
Maybe I've been spoiled by the Doubler for a while now but this head seemed fairly large in comparison and the manual is listing it at 10lbs not the 9 listed on the site. I wouldn't put this in the micro category but it certainly is still small.
Not much else to say pretty impressed thus far..