I work part time in a store that sells embroidery machines. The one thing I have seen over and over is that people buy the ones that only have 4 x 4 hoops, and before long they are regretting it.
I have a combination sewing/embroidery machine that has never given me any bad problems. My biggest hoop is 14" square and I use it alot. When they come out with a machine with a bigger hoop, I will buy it.
So - check hoop sizes before you decide to buy.