Overall, my time with taxi has been really good. I think the biggest thing that a taxi membership does is "develop your ears". Most of us who enjoy music don't have refined enough ears to hear the slight nuances that make a song great in it's sound and production. It's really like any other trade skill really... you notice things eventually that other people who aren't trained in it tend to NOT notice. The feedback from taxi, if you can swallow your pride, is itself worth the price of admission. I've made a few library contacts and finished off the winter by getting my first full exclusive instro album deal done, which is really cool. I haven't made a red cent on anything yet, but here's hoping.
But on that swallowing your pride bit, I think one of the reasons why "objectivity" in music is so difficult is because music is so often quite profoundly personal. Unlike other trades like building a house or fixing a car or whatever, music is something that is very different in the sense that it can often come from a sort of spiritual/ethereal place, and so it is harder to pin down it's essence, because it can be so subjective, and also be quite vulnerable. Everyone has an ego about everything, but in music in particular, "criticism" can be hard to hear. And there is a lot of "crossover" in the sense that I have made tracks for libraries that weren't necessarily from a deeply emotional place, but some tracks that WERE from that place actually initiated the library contact (they were pre-made before the brief came around).
I guess i just feel like there isn't as much up front acknowledgment about the nature of music itself that creators should be reminded of the personal nature of music and that a criticism can naturally feel like a "bite", but the severity of that feeling is often linked to the spiritual and sensitive nature of music itself, and that's ok. The "ego" in this sense is completely understandable because there are a lot of "vultures" in the world, and so "vulnerability" in putting your music before people is natural to resist, because in the day to day world, its' true that you don't always want to "cast your pearls before swine". But with taxi (and the forums here), I have found that people are very gracious with their feedback and criticisms, and once you learn to grow a thicker skin, it really does serve you as you go on the journey of "developing your ears" and learning to get that "developmental arc" better.

That being said, I feel like Taxi could do a better job at being upfront with people about the general statistical reality of what happens after you get a forward. It seems to me that the 80/20 rule applies here. Let's be honest. If you get a forward, odds are high you're not gonna hear back. It definitely is the long game, and you should expect to hear back from about 20% of your forwards, and probably, in the long run, you'll get about 80% of your income from 20% of your tracks (please do correct me taxi and other veterans if you think I'm off in this regard).
I think it would be wise of taxi to develop some sort of understanding with the libraries that receive their music, that the library would have some sort of mechanism (maybe a message sent through taxi so that the library or person at the library doesn't have to expose who they are), that a while after not hearing back from the library, a message from the library (maybe sent THROUGH taxi?) to the composer saying something to the effect of "thank you very much for your submission in response to our brief that we listed with taxi. Your track(s) are not currently what is needed for our purposes, but we have retained your track and contact info on file in the event that your track is needed in the future. Sincerely, unidentified music library person that you cannot respond to".
To me, this seems like a more reasonable process that acknowledges the hard work you went through and is helpful to the new taxi members who often feel like their music dissapeared into the ether. It seems that taxi could automate such a process with the libraries, and thus the composer could feel at least an acknowlegment that it was reviewed, even though it wasn't utilized. Anyways, just my 10 cents on that, if it was possible.
Also, I think a person really needs to eventually ask themselves, what do you want with taxi? Are you looking for a full time sync income? Are you looking to connect with a label for a band or singer? Or do you just want to refine your song writing craft?
It seems to me, that if you want a full time sync income, you really need to just write for the briefs, and keep your passion projects on the side (which will undoubtedly be helped by what you learn by submitting to the briefs). But if you are not seeking full-time income or fame and fortune through a label or discovery or whatever, taxi can be a great resource to just refine your chops in general and get really great feedback that can help you make better music in the future.
I'll be honest here. I deeply loathe a lot of the "popular" music in the world today. Even if I could make full time sync income from making it (saying "yes" to EVERY request from every library or supervisor request), I wouldn't want to make it, because my mental health would then be destroyed (nails on chalkboard sort of thing). And in combination with the fact that music can also be so intensely personal, for me personally, I think I will continue to enjoy making tunes (whether for briefs or for library requests) in genres that don't grate on me and wear me down. I think, often, a person can be surprised with how much they end up enjoying genres that they didn't think they would enjoy. But yet, at the same time, I think it's really important to stay away from genres you deeply loathe... that is, if you want to be sustainable and have good spirits in the long run. Play to your strengths. It seems like it is here, as everywhere, a trade off indeed.
And in regards to NOT writing "for the briefs", although I generally think that is a good idea if you are seeking a full time income, I wanted to mention that my library contacts have all come with tracks that I Pre-made before the listing existed. The process of submitting them a few times definitely MADE THE TRACKS BETTER, which I'm very grateful for, but the song long existed before taxi ever requested it. And so for myself in that regard, maybe I'm just lucky? But it strikes me that, if a certain genre is ever needed by libraries, and if you love the genre and create music in that ahead of time, that way of "following your passion" can help you get the initial library contact, and then afterwards, you can take "assignments" per se.
I appreciate all the guys who always say yes to every request, and thus make a great income from music. But the world also needs people to forge new paths and to create great music outside of the norm, and although taxi may not get you a full time income if that is your focus, it is still a great resource for refining your chops as you are putting that music together.
So this is a big thanks to taxi and also to the many great people on the forums who have helped me out, I want to pay it forward more and more to come. Thanks,
-Jonathan