I used to instruct in Enstroms and then in R22s and R44s.
Enstrom advantages:
Turbo model can get you out of dangerous situation with extra power (esp at altitude);
easier to learn to fly; good preparation for more advanced training eg. night rating, IR, turbine helis;
Can do autos and tr failures to the ground every time;
Very rugged and tough; crashworthy;
No weight limit on seat and plenty room for 2 (cramped for 3);
Looks like a proper helicopter;
Significant boot space - weekend bag for 2 no problem
Enstrom disadvantages:
More expensive and fiddly to maintain; blades difficult to keep right and lamiflex bearings esp expensive;
SLOW, SLOW, SLOW esp round nosers;
More difficult to adapt afterwards to Robbie, esp 22
Detractors would say that it has to be able to auto to the ground in practice because you are going to have an engine failure but others say that's more due to dodgy maintenance in our neck of the woods...