My HomeLink mirror with compass seems to be working quite well. Haven't driven at night yet to make sure the auto dimming works properly, but I assume it will.
Directions supplied are scant however. Nonexistent actually. If anyone buys one, and has trouble with the install let me know. The main thing to remember is that there's a Torx 20 screw accessed from below the mirror mount, near the windshield. Loosen that, and the original mirror slides up and off the mount. From then on it's just do the reverse to install the replacement one. Took me about 10 minutes after I figured that out.
Sure is nice not to need to carry the opener remote, and to have a compass on my Cross!