Sargos: I think the Sega Genesis version is still the best version out of all of them. The UI was far superior to the PC and the graphics are pretty crisp. It was overall a much better experience than the PC version.
For me, the Genesis version has some disadvantages:
- controls: no comparison to the PC version with mouse/keyboard that worked excellent. The Genesis version was too slow to control with the d-pad.
- from a technical point, the Genesis was far away from the PC version: scolling was not really smooth (especially in bigger parks with some sprite glitches), bad music/sound compared to the crisp CD sound
- no stock exchange or merchandise purchase
- no zooming-option and with this, no really good overview over your park
Sadly, there is no Sega Mouse support.
So, all in all, I think the PC version is quite the best version out there, also better than the PSX version (also no mouse support), but I never played the 'Shin Theme Park' version.
Nintendo DS port is quite good but suffers from the same problems you know from other systems like sluggish controls or a poor performance when building bigger parks.
Beside: There was never a patch for the PC version (
related to this source) despite of the flaws left in the game...
Sadly, there is currently no patch for ThemePark, despite how badly it it needed to fix up the numerous bugs. Worse still, it has been said that there is no plan, nor intent, to ever make a patch.
Still, I think, the PC version is really good and can be also a lot of fun if playing with money cheats to choke down the difficulty a bit. Other than that, there is a good starter guide on
GameFaqs.