Remember that with the sit down type you have to move the quilt not the machine.
I have a long arm table with a Baby Lock Jane. I do not recommend this kind of set up. Not enough throat space.
Also my table has large poles that take up 3 in of throat space. I think the shop deliberately sold me this set up so I would have to buy a long arm machine.
My table can be set up half size but will only be able to do small lap quilts on it.