For me, I am not happy with my Boxer. Just not the machine I hoped it would be. It sits WAY more than it goes out. Not really any problems with it, just not as useful as i'd hoped.
But, I think the X850 might be a better addition for me. So, I have a job lined up where one might excell, and give me a good idea if one will work.
I won't use one as a main machine either, more of an option when we go onto the smaller digging jobs. Basically everything I thought the Boxer would do.