Thought I'd share with you all my experience on iFolder for mac.
I've used iFolder since 1.x on windows clients and last month our office moved to using only MACs (we still have one PC for certain admin use). We are not a big office so we can afford to test everything quite well.

The new MAC client works well if you remeber to follow some steps that I try to line up here.

In a mixed enviroment the clients work quite well if you don't need to link files with each other AND don't use special characters like scandinavian ones. The links don't preserve from one enviroment to another. The special characters appear OK in one enviroment and differently in another (tested with win and mac) so the filenames get mixed up.

When first putting up the MAC client I've had no difficulties using the last opensource 3.7.2 client. It seems once in a while not to start properly or very slowly, but thats cured with quitting once and restarting it. Once or twice I've had to restart it three times.

If you sometimes have to move the folder you are syncing to a new location on your mac - DON'T revert it/ delete it and download/upload it again after the move. It will completely mess up the system (iFolder). We did and it took us three days to sort it out (if you ever stumble accross the same - don't hesitate to ask what to do).
If you for some reason have to move the folder to a new location be sure to RENAME it and resync to the server.

If your iFolder client on your mac hangs for some reason sometime (it occurs). It's usually the mono instance that does this.
I have solved this by quitting the iFolder client (it may take a couple of minutes, if it doesn't just force quit).
After this check that no mono is left running by killing all mono instances.
Do this by opening a terminal window and writning killall mono [enter]
This will take care of it.
Now you can restart the client and it usually works.
Sometimes I've had to restart the MAC itself.

To conclude
When you get the client up and syncing it works well, but be sure that it does start. I don't start it automatically at startup - just manually when everything else is up.