I have had the thermawing system installed by RDD  on my IV-P turbine a couple
of years ago.

The computer controller failed within a few weeks and had to be replaced. The
alternator failed within a couple of months and had to be replaced (involving
pulling the prop). I developed an oil leak around the prop after their
installation. Pulled prop and found that NO gasket was re-installed when they
had reinstalled the prop. The wiring connectors were not aviation grade - in
fact, they were not even OEM auto grade, but appeared to be K mart grade. I had
to replace all of them. My marker beacon antenna failed due to the install work
and had to be replaced.

When the system is on, I have a very annoying alternator whine constantly in my
headsets.

The heat units on the wing have many folds and uneven areas, particularly on the
bottom of the leading edge. I brought this up to Dave McRae (one of the 3
principals of RDD). He told me to my face "we did not charge you enough to do a
good job!!!" It seemed to me they charged me plenty, and I paid them what they
asked.

I would advise that, if you consider having RDD install this system, DO NOT
leave your airplane unattended during any aspect of the work. I certainly regret
installing this system, but have not pulled it out either. I pretty much avoid
icing situations anyway, and so far have not needed to use the system in flight.
I hope that, if and when I do need it, it does not fail at the worst moment! 

Doug Owen
N800DB