135 feet sounds pretty high, but that is only part of the equation. Also consider load radius and maximum capacity. That is, with a 135 foot boom how far will the crane reach and how much will the crane pick up at that distance? Or, more realistically, how far will it reach and how much will it pick up with 100 feet of boom?
What are the trees like where you live? Tall and skinny or short and fat? Do most of the properties allow easy access, on or off pavement?
I'd suggest going back over all of the removals you've done over the last 6 or 12 months and see how they could be done with a crane. Once you get a crane, you will use it as much as you can, even if the job doesn't require a crane.
Also, get some load charts for the cranes you are considering, learn how to read the charts and look at the crane's capacity in various configurations. Bear in mind that the charts show the radii and maximum rated capacities with the load on the boom. Because of boom flex, the crane will pick up that load at a shorter radius. Also, the capacity is a maximum. You will actually (hopefully) be picking smaller pieces so you don't overload the crane.
Read the load charts. They tell you a lot more about how useful the crane will be than just the 'boom length with jib' measurment.