I use a IOGear GBU421. It's stuck in the back of my 27" monitor so it's less than 2 feet away from my mouse. No skipping (my problem before using the dongle), no loss of connection.
There are some other dongle suggestions in that thread I referenced. I only have experience with the the one I have (cost only $8 on sale at Fry's). I have to mention it does have some "quirks", mainly dealing with initial connection after waking from sleep. I always sleep my machine, and the USB port(s) in the monitor have no power when the machine is asleep. So the dongle is off. Thus I need to wake my machine via my wired keyboard since clicking the mouse can't work to talk to dongle. Another quirk is that the MM may not initially re-connect after sleep requiring me to flip it's switch. This however doesn't happen all the time. I've learned to live with it's quirks. Maybe other dongles don't have these problems. At any rate once connected there are no loss of connection or skipping problems.
One other thing. I have a late 2010 Mac Pro. Inserting a dongle disables the internal BT so there is no problems using a dongle. If I recall that may not be the case with pre-2010 Mac Pros. That's probably why the external antenna solution was born. You have a 2010 mac pro so I assume you wouldn't have any problems using a dongle either.
