You are going to try out the machine before you purchase, correct? If so, be sure to check out the 1/4" seam yourself.
Most of the new machines allow you to adjust the needle so that the fabric can completely cover the feed dogs while you are sewing the 1/4" seam. However, this is something you need to check out in person.
Here's something you may also want to check out -- whether the needle position can be retained in memory when you turn off the machine. I love my older Bernina 1230. It allows me to adjust the needle so that the fabric completely covers the feed dogs while I sew 1/4" seams. HOWEVER, it does not retain the last setting when I turn off the machine; it always restores the needle to its central "home" position. I cannot tell you how many times I sewed yards of pieces together with the wrong seam width because I sat down at the machine and forgot to reset the neede position when turning on the machine. (Now I place a piece of tape over the knob when I get up, to remind me the next time I sit down!) This is especially problematic for me when I can piece only sporadically rather than every day.
It would be really nice to be able to "instruct" the machine to retain your last needle setting. (I don't know if any machines actually do this.) All of the machines that do embroidery have the wider-set feed dogs, and most of the nicer new machines do embroidery, so I think it's pretty normal to have to adjust the needle position for a 1/4" seam. Having that as your "normal" setting would be really, really nice for us quilters!