I hired a Timberwolf 13/75 when thinking about chippers, and echoing others comments I found 3 problems: heavy machine means hard to move around and get on a trailer, small chute which narrows makes it a pain to feed stuff in, and as a 3" chipper it is actually only happy to chip 1 1/2 to 2" without being really careful.
My solution - JoBeau M500. Self propelled so drives itself onto the trailer, 24hp engine will chip up to 5" diameter, infeed chute is 50cm wide by 15cm tall so you can shove branches in and let the chipper do the work - I never use loppers to feed this. Above 3" is firewood and it will eat anything smaller with ease as the chute is so wide. Stuff like poplar you can hardly feed in as fast as it eats it.
I believe the degree to which the chipper self feeds is the key to productivity - if you can throw a stick in and let go then you are picking up the next piece ready while it chips. This means it needs to grab in, but also be powerful enough to chip and eject without slowing and blocking. As a test I would suggest scots pine or leylandii.
The only problem with the M500 is there aren't many second hand ones around, but I paid just under £3k for mine and I know the bloke I bought if off didn't pay much more 2 years earlier. It's about 8 years old - built solid and to last.
I looked at CS100, the chute looks narrow to me which would mean hard work to feed unless straight sticks. My second choice was Haeksler, they have a 40cm wide chute machine but having bought a JoBeau I would also look at the M400.
