Went for it today with self-assessment #1, no regrets. Actually thought it felt harder than the qbank while I was taking it, but I pulled and 80% which was roughly where my last 5-10 blocks were, so I guess that was all psych-out.
Like most of the Kaplan qbank itself, the questions were overwhelmingly more detail-oriented and calculation-intensive than UWorld, but I'm hoping that's the equivalent of a hitter picking up the extra bat for a few swings before stepping up. Or in other words, hopefully on test day I can grab an extra point or two from the esoterica that showed up in Kaplan but not UWorld.
I'll probably wait another 5-10 days before subjecting myself to such a grueling exercise again (the difference between 4-5 UWorld blocks in a day and a full-length 7-block Kaplan practice test is, at least in terms of the endurance required startlingly large), but if anyone was wondering, there are a number of good questions in there and I agree w Phloston that they're worth the time (especially considering that they come w the qbank).