do you have to use a walking foot to quilt with the grand quilter, or can you use a standard foot and ease up the pressure?

I have used my regular feet for quilting, and did okay. It is easier if you have the walking foot though. Just keep checking the back for puckering as you go.
If your backing is spray starched fairly stiff, it really does help prevent puckers. Also make sure you are basting very well, too :D:D:D

would you recommend getting the walking foot?

My Pfaff sewing machine has gone south and will cost approx 600.00 dollars to repair. Is it worth this much or shall I buy another brand (Brother NX 4502)?