From what you've said and what I've tested, UBB 6.1.0.2 seems better than 6.0.5
Sadly, it hasn't got yet all the functionalities our users need. So we cannot upgrade to that yet.
Besides, upgrading to the latest version immediately isn't advisable for anything or anyone.
After almost two years of running UBB, I think we've come to a crossroad. In the coming weeks we'll do extensive offline testing for both latest UBB and Ikb3. We'll test the boards for speed (on the same server), size, reliability, ease of customization, admin options including backup, user options and facilities.
Which board will score higher will stay with us. If we drop UBB we'll probably go through a painfull conversion process. But that's nothing I'm not used to:
jan 2000 - interinc.com/ (ICU Global): our very small ubb crashed due to processor overload.
october 2001 - addr.com/ our ubb 5.46 crashed again, after reaching 1000 members.
november 2001 - addr.com/ our ubb 6.05 didn't crash, but left the other scripts without space (crashed their dbases).
We've bought 200mb of space now, so the board has the space it needs. But we'll soon give a hand to some friends and host their board too, so the next upgrade of our forum must bring the size down or else...