there is only one official, the R22 and some mods underway, like the lynx. Flight dynamics on the R22 are really really good, it does VRM, the negative G rolling, coning and such but it does not have much system depth and probably the biggest problem in the real thing as rotor RPM are concerned are not modeled: exceeding lower and upper RPM limits does not do much, as does overpitching. Overall, it has keept me many hours from flying DCS helos, so that says something. It is good but with limitations, but for VFR in some neat add sceneries it is actually pretty high in the competion.
The mods are cool but contentwise rather meh. I mean, great effort and all that and cool to have, but not really top of the pops in terms of simulation. I hope they maybe get some more love and polish:
Autorotation is pretty fun!