Great sound. Easy to use, but could be more versatile.
I purchased Ruby in a bundle with the Lion and Dream plugins. All are really -- to my ears -- top-notch models. They sound natural, are touch responsive and, as plugins go, have relatively low latency. I would make two suggestions: 1) have a stand-alone version similar to Amplitube. I often use Amplitube for practicing and writing without having to take the extra step of launching and setting up my DAW. It also reduces latency to effectively nothing. 2) While I understand that UAD wants to be faithful to the original amps, I think it's ok to add functionality. For example, I love the sound of a tremolo, but like the real Ruby amp, it's unavailable in the Brilliant channel. But that's where I'd like to use it. Also Ruby and Lion, in a stand-alone mode, would benefit from a simple reverb. To address any concerns about maintaining the look of the original amp, just don't add the Reverb control to the amp itself visually -- put a control somewhere else in the interface.