My DD has the Brother you mention. She makes quilts and has also sewn thru multi-layers of decorator fabric with no issues. i've sewn quilts on it too and really like it. yes it is from WM, she has had it several years now and it is still going strong. comes with a warrenty. I haven't used the Singer, but my good friend has one and liked it so well she bought one for her DD. they are both quilters with a bit of home dec. sewing thrown in . Theirs came from Joann's.
Personally, I would put my money toward a new machine over a used one any day.