D16 Group Phoscyon 2

I'm not going into how authentic this sounds and as one person stated: the original TB-303's vary to such an extend that it's a moving target anyway.

However, this sound amazing, and gives you the option to use the plugin more traditionally, or to make use of some superb effect and - the winner for me - their step sequencer interface. I chose this over several other emulations because of that and how it gives me the ideal combination of 'made to work in that interface' (which is optional, I point out!), and 'but so much more creative and usable than the original unit'.

All in all, this is a robust and great sounding emulation with some great contemporary features. Love this thing.