I think you will have difficulty finding that. You can find LOTS of reviews at
www.patternreview.com though, so that's one thing I would suggest. Otherwise, I'd do as suggested and print out the specs of the ones you like to compare and then go test drive them. FYI - in most cases (at least in the higher end machines) there will be a Babylock and a Brother with matching specs, because they are siblings. The differences will mostly be found in what designs are built into the machines. For instance, some Brothers have licensed Disney designs, etc.