I have the Juki on a table - no frame. I love it! I've heard that people who want it on a frame wind up buying two of them so they can have one for piecing. They are also great for tough sewing. I like making tote bags on it because it easily sews through thick layers. Mine is purely mechanical - extras are just the thread cutter and needle threader (which is a bear to use!).
But, not only is the throat wider, it's higher too. And the lever for the pressor foot is out of the way and does not catch on the quilt. I easily quilted a queen size quilt on it.
That's the pro's, the con is that its a very heavy machine and it needs to be oiled on a regular basis.
I have heard others say that if you want one on a frame, that you should buy the largest one you can afford and don't plan on taking it off the frame for table top sewing. I have heard others saying something about having to take time to adjust the tension whenever you do that. Does not sound worth it to me.