Having been around the block a time or two, my advice would be to do what would build your experience, not just build time. Obviously, everything fluctuates with supply and demand, but all things being equal, the quality of the experience is more important than just the number of hours. Someone with an instructing background has a much better grasp of the big picture than someone that has schmoozed a few rides in the right seat of a jet. (How much quality time would that be??? Talking on the radio and working the gear...maybe....). There are other ways to build time...traffic watch, banner tow, even buying into one of those SIC deals....but as an instructor you will not only be building time, but you will be continually learning and gaining experience in the REAL real world of ATC, instrument flying, FARs, etc. I would not even consider not getting my CFI.
By the way, throughout my career, in everything from C152s to Metros to Dash 8s to 757s, I have continued to instruct. It's by far the best way to continue to learn.