If you are a fan of the TwOtter, I highly recommend that you buy the latest and greatest. It is about as accurate a representation of the TwOtter as I think you could do for FlightSim. I have quite a bit of time in the airplane, so I can attest to that. The one limit that faces the modeling of all the deHavilland types is, getting the Lift/Drag performance right when the airplane is in the "STOL" configuration.
The TwOtter is a pretty straight forward airplane when you operate it 10 and 20 degrees of flap, 82 knots and below taking off and landing like any other airplane. Most Airlines and a lot of modem operators still mandate that they are flown that way. But the Twin Otter becomes quite a different rascal with really sharp "teeth" when you start working the 30 to full flap range. Full flap go-arounds, or an engine failure at this point becomes a major challenge. You have to ease the power back in to prevent the nose from pitching up and stalling....getting back to 20 then 10 degrees of flaps to have any hopes of flying away while un-naturally pushing forward on the yoke to maintain airspeed as the airplane feels as though it is levitating up, tail first....nose down. It is a sensation that is "Pure deHavilland!" This new version of the Twin Otter and the recent MilViz Beaver both do a good job of modeling the Take-off performance, and letting you feel the power of the flaps. Unfortunately the speed still increases to unrealistic levels when trying to do STOL approaches. If you practice...you can develop a technique that realistically allows you to make some amazing short takeoffs and landings.
Just Do It... you won't regret it.