They get the job done, but they kind of suck to tour on.
Had them, used them maybe 10 times, broke them, got them warrantied and sold them.  Bought real AT bindings.
Trekkers are good if you touring a few times a year and your tours are short.
They are ackward and position you very high on the ski, dont touring smoothl, are creaky and noisy, very heavy, and just generally a pain in the ass.
For some people Trekkers are a great option, but if your at all serious look into freeriders or the new Naxos.
AT bindings are much lighter, touring much easier, are more reliable than trekkers (not that downhill bindings though) and are just more functional in the BC.
If your serious about getting in the BC than they are the way to go.  You can't huck too hard on them, but anything under 20 feet or so isn't a problem if you know who to land.  They still ski fine on soft snow and the difference going up is unbelieveable.
The new Naxos are supposed to be awesome.  Pretty beefy, look down so they cant ever go from ski mode to touring mode.  Freeriders are what I currently use and have liked so far. They are redesigning it for next season and it should be improved a lot.  Depending on how the new naxos fair this season I may try and swap the freeriders for new naxos.
So, if your willing to spend more $ to get a better set up, go with AT bindings.
If you think youll only tour 5 times in a year or something not worth it to get anything more than trekkers.