start with visiting dealerships/ quilt shops, quilt shows that have machines you can (test drive) try out as many as you can- take some quilting classes at a lqs-
then you will have a better idea what you need- what you will feel comfortable with and feel you could work with.
any machine with a nice, even straight stitch can be used to machine quilt a quilt- it takes practice- and motivation to learn the (art)--not a specific machine. even $40,000 computerized machines still take some work-and a degree of expertise--and practice.