I flew the above Gloucester based TB20 IFR to Guernsey today. The GTN 650 is great and works well alongside the Garmin GTX330 and the 340 comms box we installed at the same time. We retained King 165 COM/NAV box and DME, ADF and removed a King 155 and an intercom (not needed as the 340 includes it) to make space.
We debated long the 750, but it would only really fit if we used remote transponder and comms box and operated everything from the 750 screen. None of the extra features of the 750 work in Europe. In the end we decided we didn't want to depend on one touch screen to operate everything and the extra screen size wasn't worth the big hike in price.
I think we made a good choice and I really enjoyed flying it today.
