I've got them both, and prefer GPO 4. The main reason isn't sound, but convenience. Miroslav loads a lot slower on my machine. I also really like the sound of the woodwinds in GPO - in particular the flute and oboe.

GPO also uses keyswitches to toggle articulations, so you can load an instrument on a single MIDI channel, and get different articulations by pressing MIDI keys. Miroslav requires loading the different articulations onto different MIDI channels, which is much less convenient.

I also found the GPO sounds more "playable" from the keyboard.

As a result, I really haven't spent a lot of time going through Miroslav. But every time I do, it seems I end up coming back to GPO instead.

-- David Cuny
My virtual singer development blog

Vocal control, you say. Never heard of it. Is that some kind of ProTools thing?