I have the Brother CS6000i and really, really like it. It's going strong after 6 years. As to the above post about stitches, it has a piecing stitch that is an accurate 1/4" but preset to 1.6 length which is way tiny so I bump it up to 2.0. It actually stitches as well as my $3000 Janome 8900, but of course, has a small harp which is why it's perfect as a travelling machine. I also have a Featherweight but much prefer the modern convenience of the Brother. I had a Janome Gem and didn't like it at all. No way to adjust the stitch length except the presets and the machine just didn't sew as well as the Brother.
Oh, as to the bobbins, all class 15 Brothers take a class 15 bobbin, so there's no need for a model number. A few Brothers take the L class bobbins (like the 1500s straight stitch model), but not very many.