I've used Trekkers for years and also have a dedicated AT setup with Fritschi Freerides.
Not only are Trekkers the best touring adapter out there, they are pretty much the only touring adapter out there. Back in the 90's there was the Secura-fix which was a piece of crap. I also used to use some Ramer RATs (still have them somewhere - with cracked toe/heel pieces). Trekkers are better than either of these. The climbing posts are pretty decent, they're not that heavy and as long as you have the heel throw cranked pretty tight there's not that much slop. The only thing you have to watch out for is hyper-extending them - you can break them if you're torquing your boot toe against your binding. This is pretty hard to do, though, and easily avoidable.
By comparison, an AT setup is nice because you don't have to carry the Trekkers in you pack on the way down but you also don't have a nice stiff feeling alpine binding on the way down.My alpine bindings are metal Salomon 916's,so the Freerides feel pretty flexy by comparison. This year's Freeride + supposedly eliminates the "insta tele" problem of previous Freerides, but you can still catch the heel unit with the edge of your other ski and wind up in "insta-tele". This has happened to me on tricky/steep terrain and it sucks. I've also broken the toe hight adjustment screw that holds the entire toe piece on. As a result of the previously mentioned glitches, I still use my Trekkers on any remotely scarey descents. I've never tried Naxos or Dynafits, but I probably will in the future due to the problems I've had with Freerides.
So basically to sum it up: Trekkers - not so great on the climb,but there's nothing like alpine bindings on the way down, AT bindings (at least Freerides) - good on the climbs,lighter weight, but not so great on the descents.