Sorry, but their firewall is pretty much just window-dressing, especially on a membership site where most users will be logged-in. As for "malware signatures and malicious IP updates in real time," whether that's of much use depends on how fast they are to react.
In the recent cases of plugins in the WP repo being sold to unscrupulous buyers who inserted all sorts of malware, Wordfence was extremely slow and so provided no help at all. (They have written up some interesting posts after the fact about who seems to be behind those purchases, which is more great PR for them, but they did nothing in advance to prevent sites getting infected. Investigative journalism is not security.)
Indeed, the best-known case of such a plugin incorporating malware (Display Widgets) demonstrates why self-proclaimed security expertise should always be treated with skepticism. The person who first flagged the problem was David Law. But he had recently brought out a fork of the original Display Widgets plugin, and so he was seen as a biased competitor (does that sound familiar?) by many of the self-proclaimed "experts". On the contrary, he was actually banned for a time from the WP repo because he persisted in pointing out the security issues! What did Wordfence do? Nothing.
As a user of the Display Widgets plugin myself, I am pleased to say that I took David Law seriously and so didn't experience the problems that many others did. (Someone else on this forum paid similar attention and opened a thread about it.) Then White Fir got involved, and actually called for Wordfence to get involved on the grounds that the more who did, the more likely it would be for the WP repo mods to take notice! Eventually, the repo mods did take notice and removed the offending code. (No apologies, of course!) Then Wordfence did its investigation and wrote its posts. But that was very much after the horse had bolted.
It wouldn't be so bad if Wordfence (and the repo mods, come to that) had since become more proactive, but they haven't. So the very best of luck to you!