I have two Pfaffs and a Brother and I like both brands for different reasons:
My work horse is the Pfaff ?7530? and I love it because of the built-in walking foot, needle down position, the low bobbin indicator, its smooth operation, and the stitch-in-the-ditch foot. I would not want to trade that machine.
The Brother is a low end that does nice decorative stitches (particularly the button hole for applique), it has a drop-in bobbin, and it does not mind being cartet around.
Then I got the Pfaff GrandQuilter - a mechanical straightstitch quilting machine with a large throat opening and amazing speed (control). Not too keen on it yet. I'm not sure I would buy that machine again.
I personally do not like the way Berninas handle from assorted test driving experiences. It is a fabulous line - just not for me.
Many of the quilting ladies I know have Janomes and they are in love with their machines as well.
When comparing machines in the same price category, I think a lot depends on what features are important to the buyer, how well does it handle, and which dealer will give the best deal (cost and support).
As the others said: check the reviews.