I've been with alamy since 2001, and am getting utterly disillusioned with them. I have not uploaded anything since 2011. I shoot specialty natural history, so for textbooks. The biggest problem is that alamy shortens photographers on revenue. I only sell Rights Managed images, so low volume, but in theory higher price. However, alamy finds all sorts of clever ways on shortening me on price. On average I get about 20% of the alamy posted price for specified use. It has gone as low as 3% (yes, that is a 97% discount!!!), and that is before a 50% commission. I've given up on asking them for reason, or to request rather to not have a sale, than to suffer the indignity of a dumping price. To no avail.
By now I look at the 1700 or so images I have with them as "sunk cost", but won't throw any more time/money down that rabbit hole. I think I sold about US$24K, so got about $12K out of it, purely has hobby income. Peak sale volume was in 2006-2012, since then steady decline, both in volume, and more so in $$$.
What works much better is giving talks to societies, or at specialized venues (botanical gardens). They pay quite a bit better, and I can recycle the talks. For natural history, I will only upload to CalPhoto anymore. It is for a good cause, education use is free (which I support), and once in a while I get commercial usage inquiries, where I get 100% of the proceeds.
In natural history, it's not only the picture, but the knowledge about the organism that counts. Once you are internationally known for expertise in some arcane topic, inquiries will come in. Had some of my research images displayed in the Smithsonian, which puts a much bigger smile on my face than a few measly dollars from a stock agency.
Hope that helps.