I also use a Bluetooth gps to drive a kind of a junior varsity EFIS on a handheld - but my hardware is different on both ends than yours. I use a Teletype GPS and a Palm T5 running Flightmaster software (
www.flight-master.com) and I love it. The Bluetooth connection is rock solid, and the lack of extra wires all over the cockpit is a real nice convenience.
There's a trade-off for that, certainly, in that since both the GPS and the handheld run on internal batteries and not ship's power, I'm limited to about three hours of flying before one or both needs a recharge. Not a problem for me, given the kind of flying I do, but it could be a real limitation for others - in fact, the only people I would NOT recommend this combo to are the serious cross-country guys.
Both the Bluetooth connection (and the Flightmaster software) get a big thumbs up from me.