I have the Brother LX-3125 and have been very happy with it. Very basic, inexpensive machine, but it does the job quite nicely.
If you line up the edge of your fabric with the outside edge of the feeddog slot, I get a very nice scant 1/4" seam on mine. Just enough scant that you can square up a D9P nicely and still have a true 12-1/2" block.