Well, first off, the rogue and the MG-1 are almost exactly the same synth, so dont discount the MG. The only differences are: (1) the rogue has a pitch wheel, the MG doesnt (2) The MG has a polyphonic section, the Rogue does not (3) the MG has both RCA and 1/4" outputs, the rogue only has 1/4" (4) generally speaking, people have been paying more for the Rogue then for the MG-1 just because the MG says "realistic" on it instead of "moog", but rest assured, its all moog innards. its fully a real moog synth.
Next, the Prodigy is a great synth and more versitile then the mg/rogue, but it'll cost ya probably an extra 200 bucks over the MG.
Lastly, the Opus 3 is a string/brass/organ polyphonic synth. For what you seem into i wouldnt go with it.
I'm a fan of Thursday too, and I own an MG-1. For someone just breaking into synths, the MG is really a great start. The prodigy could be a bit too much for someone just starting, and the rogue is virtually the same instrument but costs more and has no polyphonic section. For my money, i'd go with the MG-1. Good luck!