I have little if any experience of other mixers than Hobart. Here as some
things that might be of interest with the 20 qt.
The Hobart 20 qt also accepts a 12 qt bowl (naturally, you would have to
buy the 12 qt accessories, dough hook, etc.). The 20 qt also has a power
take off on the head. The power take off accepts a grinding attachment and
slicer. Grating disks can also be used in conjunction with the slicing
head. There are a few more attachments that fit the 20 qt, the ones I have
outlined are the major ones.
Allow me to assure you I neither work for nor sell Hobart
equipment. However, as a chef I have used Hobart for many years and been
happy with the mixers. They are not cheap, a new one is $2500-$3000, a
reconditioned one $1250 up.
Hope this helps.
Victor