Oddly enough, I was just editing the lastest wedding I shot and I'm not experiencing the same performance slowdowns.

I have two theories on why that is:

1) Adobe released an updat that addressed some of the performance issues or
2) The performance issues come about later in the processing workflow. For instance, once 100 images are edited, the program must compile all those edits and store them in memory. If you're early in the editing process, there are less edits for the program to buffer.

I have no idea if #2 is even plausible, but I won't know until I get about halfway through the edits.

From what I've experienced early on in this most recent wedding, I'd go with the most recent version of LR. Stay tuned.