I'm trying it now. I've tried them since 4.1.0. There are still bugs and problems apparently, but the only bug I'm annoyed with is the logging. It duplicates entries in the logs when you enable logging to unopened ports and don't have any rules. Not a critical bug, but it's hard to believe they can't fix it after 2-3 months. So I imported my Kerio 2 rules and for some reason the logging problems pretty much goes away.. almost. :)
Otherwise it seems ok so far. A little high on CPU usage at times, compared to others.
I guess it depends on how curious you are about 4.1.2 and whether you have the time to install/uninstall and play with it.. It does have stateful inspection now, which is nice, and 4.0.16 does not. That's probably the main improvement/advantage.