Typically 40-ish screeners work per month. Sometimes as many as 50-ish.
They range from hit songwriters to former A&R people, to former and current publishers, to people who've done song and instrumental selection for years at music libraries, to music supervisors, to music coordinators working on big TV shows for top music supervisors, etc. A few of our screeners ask to have their identities not posted as they work for TAXI between shows, and don't want people in the industry to know that they ever have down time
NONE of TAXI's A&R people are interns or second stringers.
I think people like to question who the screeners are because they can't imagine that anybody with a ton of experience wouldn't automatically hear their genius and forward their music. Usually, by their second year of membership, those geniuses make comments like, "I can't believe the submissions I was making my first year, I was clueless." That happens ALL the time, but nobody believes us until they've had the same revelation, or if you prefer: epiphany.
The screeners are assigned to genres they've been cleared/approved to do. Some are only cleared to do one genre, but a handful are cleared to do a few genres. The interesting things is, a screener who was the music intake person at a music library is MUCH better at identifying (let's say) Hip Hop tracks for TV than somebody who has produced huge Hip Hop records. The music library person is looking for what works in a TV show, the big shot producer is looking for hits. Two different skill sets and two different circumstances.
I've noticed that this is only your 5th post here. It's very common for "newbies" to doubt the screeners. And just so you know, we've actually got a Head Screener who CLOSELY monitors their work on EVERY listing. If you ever have a question, you'd be smart to email our head screener.
Also, you can get a really good read on how right you are, or how "wrong" the screener was on a particular listing/critique by posting the full listing, a link to your music, and the FULL critique in the Peer-to-Peer section of this forum. The first few people to respond are often other new-ish members and can sometimes be overly kind in their assessments. The balance of the respondents will typically be much more experienced members who will give feedback that's also kind, but also very insightful and helpful. On the whole (and feel free to chime in here veteran members), the feedback from the experienced members will be about 98% in line with what the screeners have decided. We've all been to this rodeo at least a hundred times on this forum, and the outcome is always, 98% agreement with the screeners.
I COULD be way off base here, but IF you're feeling like, "Who are these people and what qualifies them to judge my music and determine if somebody in the industry is going to hear it or not," you'll save yourself a lot of time and wasted effort if you do what virtually every one of our successful members has done: realize that the screeners WANT to help you, and they are not sadistically trying to hold you back. Ask ANY of the members who have posted in SUCCESS STORIES on this forum, and they will likely all tell you that.
I hope this helps!