The biggest drawback for us is that the rates look very expensive to the uninitiated.....................
...and this is the biggest problem. I'd love to go back to charging by tacho for all the good reasons given but from a marketing point of view, it's a big 'no-no'. Great for a group but not for a Club selling flying training.
We're currently charging for the time shown on the ADF timer, as there is an avionics master switch and it comes on with that, so there is some warm-up time before charging starts and it's probably pretty accurate. We note the time to the nearest 5 mins anyway, for instance 45 mins if it says 47. Since we charge decimal, you only pay .7 for 47 mins, which is a pretty good deal!
Now we'll thread-drift into whether or not you should keep your logbook in actual mins or decimal!!
TOO