I do not have any official test, but I can say compared to my fenix 5, the 935 Ant+ connectivity and BT seem to work much better.
BT works over much longer range and does not drop and reconnects quickly when it does. I tested across my house and it didn't drop until the furthest parts of the house (and I have a pretty large house, 7000 sq ft).
Ant+ connected to all my bike sensors including Garmin Speed, Garmin Cadence, P1 pedals, Varia Radar and Varia Vision and did not drop any during hour+ ride today. I also tested with Stages in same trainer that did not work with my fenix 5 and I had no issues at all, connected quickly and did not drop during my short test, while f5 dropped the Stages immediately.
Overall comparing my fenix 5 to my 935, the 935 for BT and Ant+ hands down is the better choice. Everything just works for me on the 935.