I liked the two I bought. Not a lot of power but very agile and well put together. $15,000 should buy you a low hours 320 with a trailer and a bunch of attachments.
I have and love a 320, but before you buy there is one major thing to be aware of.
Boxer did a recall/replacement of engines on the 320 because of overheating and engines seizing up. When the engines were replaced with new engines that had an external air filter they received new hour meters so the hours on the machine may not be accurate as far as the entire machine goes, there are a lot of moving parts that get wear that are not part of the replaced engine, so you need to do a careful inspection.
Bought mine used in the winter of 2012/13 on Ebay with a trailer, bucket, leveler, trencher, auger head only (no bits), and forks for $9500 and drove from Ohio to Atlanta and back to pick it up. I did a lot of research and spent a lot of time waiting for a good deal. It had 400 replacement hours on it and had run great with only a little maintenance. I did have to replace the quick attach plate at the front (@500 from Morbark who bought Boxer) after I used it for pulling a bunch of stumps after a storm. I have purchased a tree boom, grapple bucket and reese hitch plate for it and we use it for something damn near every day. I can pick up @800 pound logs and load them as long as I am slow and careful, I have tipped the whole shooting match over before with a log too big, but the machine wanted to lift it, I just wasn't fat enough to counterbalance
DDave