Funny, I prefer the front load bobbin because I can change it without having to remove my quilt or embroidery hoop! I can tell from the noise when I'm getting near the end.
A larger harp is probably what I'd notice first. My "dream list" would be a large harp, stitch regulator, large bobbin, dual feed... well, something like the Bernina 8 series but without the high price tag!