Telstas are a hell of a truck. They are awesome for stringing cable.
But... for tree work, the thing I dont like about 'em is that a Telsta T40C is only going to give you about 42 feet in working height. For alot of trees, thats enough, but for alot of trees, it's definately not.
My dad has a B-I-G tandem-axle Intl with a Pittman digger body on it. The max boom height is 56 feet, I think. It's used for setting power poles, which I think it can set 65-70 foot poles no problem - Big Class 5 poles.
The thing has a pin on bucket, with a 5k winch and jib up on the tip of the boom, so I'm thinking I may try and talk him out of that truck if/when things get busy again.