I don't have any experience with the AP mounts, just comparing the Taks, so take that for what it's worth.
First, since I had no manual and I was on vacation at the time, I stupidly thought I could use my NJP's 24V inverter to run the EM-500, but since it's not 24V, I fried an IC on the EM-500. No worries, I thought, since I planned to upgrade it to Temma-II when I got home. But that turned out to be twice what was originally estimated by TNR to do, so I went with a Sidereal Technology servo kit instead (for about $800). Works GREAT now (and was surprisingly easy to do, and completely reversible if necessary).
One thing that surprised me is that the EM-500 isn't much harder to set up than the NJP, thought it's quite a bit heavier. Mine has the spun-cast pier, which is really heavy, and probably the primary reason I don't set the mount up as often as I would like.
But the EQ head isn't hard to set up. Maybe about the same as the NJP. I think that this is because it's smoother, so it doesn't hurt the ribs so much to cuddle it while moving it from my shop to the pier. The NJP is all angles and protrusions.
So far, I've only had my 12.5" f/23 Cassegrain on the EM500
It weighs about 45 or 50 pounds (I've never weighed it), so it's far from loading the mount. I'm hoping to piggyback a 6" f/10 Jaegers and maybe an edmunt 3" f/15 on it with no ill effects someday, but not until I've got an observatory enclosure for it.
Next to moving that pier, putting the OTA on the Cassidy saddle at head height is the lest fun part of the job - but that would be true with any mount.
Polar alignment is easier than for the NJP, because the head can be rotated on the pier through 360 degrees, so the only pier orientation you might want to worry about is getting one leg about north (for stability). Takes no more than a few minutes to polar align and get to viewing or imaging.
Tracking is fabulous, and I doubt I'll miss PEC with a 3" PE and autoguiding any more than I do with the EM-10 and NJP.
The Sidereal Tech goto kit has a bunch of cool features that I haven't had the chance to try out yet, including their PointXP and spiral search routines. I saved money and bought the tethered hand controller, though they do have a wireless option.