TV, We run a 23 and a 17 ton at my work. Both Nationals cranes mounted on ford trucks. The 17 ton is a work horse. Nimble and small, it can get in some tight spots that would make bigger cranes have to sit on the street. Like the one guy said; It made my boss a lot of money, built us a new shop, and made the $ to buy the 23 ton. Lots of guys talk about these 30 ton cranes and bigger, and I'm sure they are very nice, but unless you are the man to call for the monster trees in your area, a 17 ton gets down with the best of them.
However, if you can go a little bigger, then I would suggest it, because the positives out weigh the negatives. The 23 ton we have is pretty damn versatile. 104 foot of boom, plus the jib (we never really use it). Still plenty nimble and all you need is sheets of plywood to get in a yard. In the summer months, we usually can just drive right onto the lawn and you would never notice. It is a front mount and we just load all the saw logs, firewood logs and big nasty stuff right on the deck. Saves time and $, plus it allows use to keep the saw logs in proper lengths. It has the muscle to pick big logs and tops. Usually the landing zone is smaller than what we can pick. Eiyher way, a bigger crane is just another feather in your cap.
As always, a good operator is a must to accomplish the extra productivity any larger piece of equipment can produce.