From what I've been able to gather, FSOne isn't much of a heli sim at all. Most people seem to think that Phoenix is the sim to get if you're serious about Heli's. They even released a Blade 400 model recently.

I personally went with RealFlight G4 before I knew other sim's existed, and it's actually really nice. They have a virtual flight trainer that has 3 "pro" heli pilots showing you various moves and explaining what they're doing. You can see the transmitter sticks, so you can copy what they're doing when you start learning how to do 3D. They also have a heli orientation trainer where you have to learn hovering by following a computer heli from point to point, maintaining a hover in a specific spot. Do it several times, and it switched you to nose in hover... which is a lot harder. So it does have a lot to offer the Heli pilot!

Unfortunately, the fanbase behind G4 seems primarily airplane based, and almost all the models come from the fanbase... So while a Trex 500 showed up shortly after it was released, the Blade 400 is still nowhere to be found. I use a mini-titan as the model for that, since it seems a little less forgiving than the Trex 450 model, which gives you a false sense of confidence (because the model is so stable).