Microrock Pro

Microrock Pro is a unique instrument in that it combines a synth and guitar (or string) modeling to make sounds unlike the usual analog synth emulations heard in many software instruments.
For someone who is coming to keyboards and synths from a guitar background, the interface makes it easy to find sounds. The control for positioning a guitar pick anywhere along the string is intuitive, and will be intuitive for non-guitarists as well once its tested.

The sounds are mostly like electric guitars played through effect units, and there are a wide variety of tones that can be made either through tweaking a preset or starting from scratch. The pick and pickup tones, combined with distortion, delay, chorus and wah filtered through the common synth ADSR controls provide a lot of variety. I find it most useful for lead lines, as if playing a MIDI guitar or a densely effected guitar. You can simulate power chords also, though.

CPU usage was light on my Powerbook, which is a nice bonus.

The presets are handy for trying out varied sounds, and while there aren't a ton of them, they are sufficiently spread out in the sound spectrum.

Support is quick and friendly in the KVR DashSignature/NuSofting forum, and is also responsive via email. Microrock Pro has never crashed or behaved oddly for me and my questions about it were answered fully.

With the low price and high quality results, its an easy 10 in terms of value for money. Another plus is that its fun to use - quick and easy to play with the settings without getting lost. Highly recommended.