I think that #1 corp is Weyland or NBN depending on the Meta of runners that you expect.
NBN's benefits are in the ability to attack a resource based economy, which is strong if the runners are playing Kati Jones, Professional Contacts, Daily Casts, Workshop, Pawnshop, Wyldside, etc. They also have Closed Accounts to punish money hoarding, or Account Siphon.
They are also strong against rig setups that are costly to run remotes with, because they can play Never Advance, and the runner who cant afford to just keep running things will eventually have problems.
Of course, there are tons of different NBN decks possible. NBN has the most different viable strategies of any corp. The strength of NBN primarily comes down to Astroscript being insanely good, and cards like Jackson Howard and SanSan being very strong, saving you influence (compared to other corps splashing them).
Weyland is very strong overall, and I think more straightforward. It has more raw power, and the deck is easier to construct well, imo. It has the benefit of having a strong alternate win condition while remaining good at scoring agendas.
HB Fast advance is a clear 3rd to me. But its still definitely viable. Its kindof like playing the NBN deck, with a bit more economy, but without the chance to punish the runner's tags or wreck their economy.