I see a lot of talk about 139’s. What are they really good for?  

Students need to concentrate and get a handle on the basics of flying before they start dealing with complex helicopters, of which the 119 is borderline but the situation is just too much for most beginning students in my experience.

The 119 is basically first or second order tech and has to be watched and coddled carefully.  From greasing moving components to balancing tail rotors often it is nothing to be underestimated as to its down line impact if PM is not accomplished in a timely manner.  

One cannot be ham-fisted with the 109/119 series.  Properly maintained the dispatch reliability can be above the 90% range if parts and tech support are sufficient, which is historically not a strong point for the manufacturer though has improved over the decades..  

The TH57 was an excellent starting point for beginning instruction, rugged, dependable, forgiving, simple and predictable.  Did 2000 hours (22,500 TT overall) in OH58/206 - had a blast.