How much research and hands on testing have you done? I find it interesting that you have it narrowed down to the two most expensive options currently on the market. Just because something costs the most doesn't necessarily mean it is the best. Because you are in Houston, you may wish to postpone your decision until Houston Quilt market in the fall. Every major manufacturer will be there with demos set up for you to try out. I have a stand up longarm because I am a "move the pencil" quilter (as opposed to move the paper which is what you are doing with a sit down). I also hated the sandwiching process with a white hot passion and that step is eliminated with frame quilting, but you need to have the available space, which you do not. I think you should evaluate every sit down brand available and the Houston show would be the best place to do it. Then you need to decide what features you want the most and what kind of customer support you will get. Make a list of all your pros and cons, what is really important and what you can live without. Many sitdown quilters don't need a stitch regulator. I couldn't quilt as well as I do without one.
Just as important, or even more important than a large throat, is having the needed support for the quilt. A very large table that the machine sits flush in is critical IMHO. In addition to a table, many sit down quilters have set up hanging systems from their ceilings to support the weight of the quilt while FMQ on a sit down mid arm or LA.