We bought a large sized one almost a year and half ago.   They work great, gets so hot inside that everything that can burn will burn.   We've only just dumped out the ash once and it was all unburnable stuff.   Easy to dump, hold over our old pit with the skidsteer and pallet fork and release the bottom.   Wife thought it was a waste of money but she's come to like it.   Worth the $2000 that it cost.