I have been actively using v3.0 since its release.
The following are issues that I hope to be resolved. Some have been mentioned by other forum users.
1) I really like the dual monitor support. I have been connecting to a dual monitor server from a single monitor viewer. In full screen mode, the automatic panning function between the two remote monitors is excellent. However, I think that the panning should only happen if one moves the mouse all the way to the edge of the screen and holds it there. Currently Radmin pans to the secondary monitor if the mouse is brought anywhere near the edge of the viewer (maybe 100 pixels or so). The problem is that if one just wants to use a scrollbar on the edge fo primary screen, just the act of trying to select it with the mouse causes the screen to pan and switch.
2) Is the toolbar item "Choose remote monitor to view" enabled now? It doesn't seem to do anything on my system. By the way, is there a maximum resolution supported by v3.0?
3) It would be nice to have your splash screen come up immediately during the connection process, rather than with the current delay. I always use Radmin from shortcuts with commandline switches and it would be nice to have some immediate feedback when the program has been invoked.
4) I too would like the toolbar have the ability to be hidden/shown with some sort of keystroke. Also, a command line switch to hide it would be excellent.
5) I too would like some way to hide the tray icon. I just prefer not to have the clutter.
6) The remote cursor modes are not enabled as far as I can tell.
7) I have the same nonsense characters in the viewer title bar that other users have reported.

The speed of Radmin is excellent. The only issue that I have encountered so far is when I have tried to use the screen clipping tool in Microsoft OneNote - this seems to use some sort of screen overlay. The mouse tracking becomes exceptionally slow in this circumstance. It might be worth your investigation.
Thanks