I haven't used them with pivots, but have with PX (dildo heelpiece) Pretty sure they have the same problem as the pivots, and that is that you have to use a heel lift all the time or your boot hits the dildo. it blows, but its doable as long as you don't have a long, flattish approach to what you're climbing.
I've just got myself a set because i want to do some short climbs but don't want to remount my JJs with dukes.
Sure they are heavy and not that natural to climb with, but it works, means you can use your favourite skis in the backcountry and when i'm riding down i can send it hard without worrying about equipment failure.
I used to have Trekkers & FKS. If you adjust the trekkers properly it's fine, you get about 2mm gap at the heel. If you can't get it to work then build a 10mm riser out of wood for the heel, a friend of mine did that for his old Look bindings to make it work.
Yeah Trekkers suck but for short easy uphill you can make them work. The worst part is the added weight/space in your bag on the down.
Honestly I think Trekkers kinda get dogged a bit much. If you adjust them tight, put them in binding first by hand then clip boot in & keep screws tight they work just fine. I did bunch of 2000> climps this season with no issues. Buddy have new pair that failed first time out though cause he did not check the screws but I had spare with me so was all good. Yes they take up some space in pack but I like the fact of being able to use any binding of choice.