I realized I wasn't seeing anything because my membership had expired (oops), though I'm surprised they didn't send me any communication about that.
I like Theater Extras! I think their interface is a little easier to use but it can sometimes be a little more competitive to get tickets (and they don't send you emails for every new event so you just have to keep checking). Gold Club would sometimes have different dates but a lot of the major shows will have overlap. If you visit LA, they also have offerings there under the same subscription too, which is nice. Cancelling is also easy if you do it more than 8 hours before the event (you don't get a refund, but you do get a penalty charged if you're a no-show without cancelling).
There are some sporting events, offered at around $20, but I haven't picked up any of those tickets so I'm not sure what that's like. They've definitely had Sony Hall shows before and I didn't check if there was a surcharge but there isn't one for Birdland (though the minimum is still in effect). The shows are generally mid-profile Off-Broadway shows, things that I've heard of and had on my radar, but not necessarily the shows that have had their own threads on this board (though some of them have), with a couple larger shows thrown in occasionally.
I believe you can sign up for Theater Extras emails without subscribing, where they'll list some of the shows they have available, but feel free to dm me if you have more questions.