In terms of comfort, I would likely choose UA or TG. In terms of service, I would probably choose NH, SQ, or TG. In terms of inflight entertainment, I would choose SQ or NH. I guess it all depends on whats important to you. Personally, I find comfort to be most important, and would choose UA or TG.

Also, in terms of the stopover, I don't think that you are allowed one in each direction. I believe that you are only allowed one stopover, which can be used on either the outbound or the return.