I don't, though I have it in the field working with Crestron products, with which it works well. I use it with Lutron Homeworks and homeworks drives my automation tasks either directly (lighting & shades) or as a "middle man" via contact closure.
I'm not personally a fan of the whole two-way thing (aside from digital media library type stuff). It's not that I see it as a negative per se, but rather that it costs far too much to do too little. There are certainly cases where feedback is important, but that's usually going to be in a large residence or a remote residence that doesn't have full-time management.
If it's just you in a "normal" sized house, I can't see the need to know what temperature it is in rooms that you're not in or whether windows are open or closed. That's just me, though, and I've certainly designed very capable systems that do just that for clients who want it.
If you wanted a sort of two-way command center, Crestron is the de facto standard, though Savant, being Mac based, has been tempting me to explore it more deeply. You would be able to get full feedback on a touch panel and monitor not only your AV, but other resi systems.
And yes, you can absolutely control B&O functions through non-B&O interfaces. My favorite move is (when in conjunction with a Lutron system) to dedicate a two-gang keypad w/ IR as the ML eye instead of the PUC and give it volume and track/channel up & down on one side and a source list on the other.
At the end of the day, if you want simple and comprehensive interaction between B&O and other systems, the MLGW is an absolute must. If you need any help designing the system you can PM me and we can start a dialog.
There is scarcely anything in this world that some man cannot make a little worse and sell a little more cheaply. The person who buys on price alone is this man's lawful prey. - John Ruskin