Not an answer to the thread question but...the part of me that dabbles with forum software was curious to see what sort of upgrades you were planning, and started lurking about where I found your thread on the blank pages. We used to get that on an SMF forum I admin as well....reloading the forum software and rebooting server did nothing in our case. The blank pages went away after recompiling php and mysql. Just thought I'd mention it in case it's something you're still looking for answers on.
In response to the original question though...I tend to favor SMF, from both an admin standpoint and from a user standpoint. The new RC out seems to work pretty well, and their converter did a pretty good job when I played with it, though I didn't have as many mods as here. From a user standpoint, this forum/smf does a pretty good job at keeping your unread posts straight, which is a biggie for me.
Everyone has their preferences...one thing that throws me off is the first breadcrumb(included screenshot if you're unsure what I'm referring to) takes you to the portal home page instead of the forum index, but it may be that you guys intended that.
I imagine the "members online" on the front page, with all the avatars, doesn't look so full usually - right now it takes up a lot (relatively) of screenspace, but I could see for when it's just your smaller group it may be nice.
And just because....atta boy! :disted: