I've followed the Westgate/Hilton SC entries and results for years. For years and years it hovered around 250 to 350 entrants. Then it had a big boom thanks to longer signup, more publicity, having the WSOP (poker) explode, and allowing proxies for anyone to enter just by making a spring or summer trip to Vegas. This gave the Westgate lots of "dead money", entrants which almost no chance of winning. It also seemed to cater to touts who wanted to take a shot at getting great publicity with a high finish. They even implemented a fraudulent practice of changing a tout's handle from a vanilla description to an identifying one only after a Week 1 "success" until I detected it and called them out. With aggressive competition now, the Westgate SC has obviously peaked as of year before last. The Westgate Gold SC remains a good value for the big player ($5000 per entry).
Definitely, Circa took advantage of the Westgate weaknesses especially the 8% rake. Doing just one Circa entry @ $1000 is less investment than the Westgate minimum of $1500, but you can do up to 3 Circa entries. It is by far (best EV) the superior NFL contest. The Circa had a slightly higher overall ATS record (perhaps less dead money) and pays fewer places, but still has more value due to no takeout and other features, The Circa NFL Survivor Contest is a real hoot for the contest player.
Good luck, no matter what your choice.