It all boils down to what you want to make on it.
With a 7x12, you will not be able to make longer pens. The 12" distance is from the faceplate to the tailstock. Subtract the thickness of your chuck for holing the blank, the length of your chuck for holding your drill bit, and the length of your drill bit to figure out how much pen you can actually drill. In my experience, that is about 4.25".
I have a 7x12 and wish I had gotten the 9x20 almost every time I use it.
The other thing to bear in mind is that not all of them are made equal. You mention the HiTorque, so I assume you are looking at Little Machine Shop. If not, I recommend you do. They go through all the ones they get and clean them up/check them out before they ship to their customers. They are a great place to deal with.