This is a very nice sounding guitar amp simulation.
Very good quality - not only - for a free plug-in. I know some commercial amp-sim plugins, which sound much less convincing.
The clean as well as the overdriven sounds are very convincing, without the often heard too sharp, too shrill or too digital sounding higher frequencies, the - compared to a lot of real amps - even luxurious pre- and post-tone shaping controls allow a good (fine-)adjustment. Just sounds right. The overtone reproduction and dynamic reaction also is very good, the general tone is very naturally sounding, doesn't over-colorize the original signal, plays and reacts very much like a good real tube amp.
The general sonic character for me is some very good, in a positively sense more vintage based tube amp tone, but - if wished - with much more gain, even decent high gain, so, depending on the tone controls you easily can adjust some nice, more American as well as more British sounding tones.
The modulation and delay section work fine, although I personally mostly prefer a pure amp tone, but nice to have these options already built in.
Works very well with different cabinet/speaker IR's.