Would you be content to sell a few hundred images for much less than the price (per image) of a cappuccino at Starbucks (often to commercial clients with RM budgets), or sell less images (rights managed) at higher prices? Are you aware of what RM fees can attract? Have you gauged what your competition is like at Alamy - RF and RM? If your work is at or near the top (creative) and the top contributors are mainly RM, the answer should be obvious.
To highlight one example I was approached (via my own website) by a major US company to use one of my images for 50,000 posters and multiple national newspaper adverts. Before they discussed usage or price, the option to purchase RF images for a few dollars was mentioned. I suggested RF was the best place to go then, before bothering to discuss matters further. They came back to me and purchased the image at RM prices without any haggling. It would have taken hundreds of RF sales to match the RM fee. I asked them why they ended up using my image - it was chosen because it suited their concept better than any image available online.
There are only a handful of people making substantial RF sales such as Yuri Acrus (very polished warehouse set up with, high overheads for models alone). At the other end of the scale and more common are RF contributors who only receive a few pounds for their labour - my local optician told me this was the case with her partners istock sales over a period of several months - 30 images for a total of £9. Of course there are those in-between the extremes.
After making a RM sale (from your own website) always ask why the client prefered your image and if the RM price was competitive to help your business model. On several occasions I have been slightly more expensive than Getty RM but they have still chosen my image. Of course I lose sales for various reasons.
I don't use the RF model.