My company is the west coast distributor/technical support. We went with a 23gt many years ago, well before we got more involved with Teupen, and that first model we had was a bit troublesome. Lots of little issues that kept keeping the machine down. Many of those issues on the earlier models have been dealt with.
But the back yard access was a revelation (see dead rotten trees, giant hedges, etc.). Even the front yard stuff we do with it was not possible with normal bucket trucks because tight spaces and soppy lawns. We upgraded to the version with hydraulic track height adjustment and love it. You have to do your regular cleaning and scheduled maintenance on these machines though, you can't get lazy or you will have to get a technician to work on your machine.
We got rid of our bucket truck and go with the Teupen for all of our lift needs. My guys love it, and we have contracted with some of our competitors to work on trees that were unclimbable and inaccessible with a regular bucket truck.