First, let me thank you 1000 times for developing this app. My experience with MTP on OS X has been absolutely horrid. I played around with fuse and mtpfs but found it even less stable than Android File Transfer app.
I would love to know a little bit more about how you pulled this off (if you don't mind sharing).
Anyways, I got it to work on my galaxy nexus and mbp running 10.7.3.
Here is my feedback:
1. File coping from the device works for the most part. File copying to the device is a little buggy. I always get the "The operation canít be completed because you donít have permission to access some of the items." finder error.
Console shows " Finder Unable to quarantine `CMMusic.apk': 1" everytime.
I'm guessing this has something to do with fuse.If I try to overwrite a file with the same name it asks for os x admin password which is a little weired.
2. it should be mentioned in OP that USB debugging should be enabled.
3. It'd be awesome to automount the device as soon as it is plugged in. The device should also get unmounted when it's unplugged.
4. You could make the helper a lot more awesome by adding Growl support so that a notification is displayed when (un)mounting is successful or if there is an error (mounting unsuccessul, no device, no usb debugging, no fuse library, etc).
5. Nitpick: Reveal device should probabely open the root level of folder not the folder itself (/Volumes)
6. Nitpick: Widget icon is low res on xhdpi display.
For a 1.0 release,this looks extremely promising. Keep up the great work cyansmoker!
Galaxy Nexus GSM