The 135 has a few little "quirks" but all completely understandable if you stand back and take a look at what is going on behind you.
Relative airflow from the forward quarters either left or right will induce some yaw instability from the wake of the horizontal endplates. Nothing too obtrusive but may screw up your camera shot. You can fly around it if you appreciate
what is happening but nothing to get too concerned about. They removed them on the "3" and increased the height of the fin tip cap.
Another factor is the "A of A" of the fin. It can upset you a little more than a conventional aircraft but again not much to be too concerned about. Just be aware that as per the RFM a "run on" is NOT recommended with loss of TR drive.
Reason being you will feel fat dumb and happy until the fin stalls and loses effect which you probably won't recover from. Hence the recommendation to perform a full-on autorotation.
Authority - no issue - the thing will reach 65 knots or more sideways at the stops.
Power - yes it can use more in the hover. And conversely less in the cruise.
Like a lot of these things too much BS gets read into it. Your the "pilot in command" - just fly the thing - don't ever become a passenger!!
As alluded to in the report - "Light helicopters with low experience pilots are the preferred victims."