I have a 24" Fusion, and 16" is about the max I'll go with. It's not a real big deal unless you have quilts on point and want to do a pattern in the block.
I upgraded from a 13" machine, and sure do like the extra room!
I also started out without the robotics, waited about a year to get them as I didn't think I'd like it all that much, but am finding I really like using that when I've got a gift to get out in a hurry, and an all over meander will be perfect for it. DH also likes the robotics, and he's done a few quilts too. So far, he's got no interest in free motion work.