Syncaine TM-200X

Despite the extremely cheap price tag, the author has actually allowed free registration through the download page if it is not going to be used for commercial purposes, which I think is more than fair of a deal.

This synth is essentially a supersaw-type of instrument, but it is more than capable of getting different sounds together, and is aimed to the tranceheads that suggestively can't be bothered purchasing expensive synthesizers or the likes of Vanguard (vintage-2000's), Sylenth1 (expensive) or the (now-insolvent) Superwave synths.

The sound quality on this is more than excellent. It's clean, and has it's own DSP inbuilt. It doesn't seem to use much CPU. The factory presets are adequate enough for the user, and the interface is simple enough even for the most novice, to understand how the sounds work. Forget documentation. It's got some but I didn't bother with it.

It's a highly recommended VST instrument because it's just something that's so simple and easy to use, and is readily available. (Much to the disdain of Superwave) One of the best alternatives there is out there.