I would suggest going a little higher, not much, and getting the Brother 770. You can get it on Amazon for under $600 and it has the 5x7 hoop. I just downsized to this machine. It's a nice one.
http://www.amazon.com/Brother-PE770-...ds=brother+770
I think you would outgrow a 4x4 hoop very quickly. The versatility of having the 5x7 hoop is huge compared to the 4x4 hooop - and with no tax or shipping charge, you can't go wrong with the 770 on Amazon.