Hi Michael, a few items I have encountered (which probably have been reported already):
1. After using V3 for a few hours with opening and closing multiple windows the following occurs:
a. Attempt to drag an object or attempt to drag a marquee around an object, the entire drawing - desktop and objects - move in unison. Also, objects with their rotation handle showing, cannot be rotated and again, everything moves.
b. Text upper and lower cases work opposite of normal activation, i.e., with caps lock 'on', yields lowercase and with caps lock 'off', uppercase. With caps lock 'off', the 'Shift' key is used to access lowercase and not using the 'Shift' key, uppercase.
Quitting the app and rebooting it restores normal operation.

2. When renaming an object via the 'Edit Object Name' dialog box and should one wander out of the box (partially), the highlighting ends and starting over is a must.

3. Double-clicking a .3dm file created in Moi from the directory opens Mac's TextEdit app with content like the attached image.

Otherwise, still enjoying Moi!

Leonard