I'm probably the oddball on this board as I have 1 machine. I really can't advise you on the Brother machines but why buy 2 machines if you can get 1 you love that does what you want it to and has all the features you want. Go back to the store, take some quilt sandwiches or even a small quilt to make sure you have enough throat space, and try each machine again. Focus on what you like/don't like with each one.
I went several times and tried several machines a few times before I settled on my Juki. I preferred it over a few others because it was quiet, sewed well, good harp/throat space, and had all the features I was looking for. I don't make bed-size quilts right now but if that's what you want to make, I would consider 2 machines ... 1 with a really large throat to just quilt with. Good luck. You will find the machine that feels right for you and that's the one to buy.