Let's talk about CurseForge.
Here are my impressions, a month later.

The idea
Let's start positive and talk about the idea: a store where you can find mods and packs for your favorite games (not just Minecraft).
Here users can find cool stuffs and authors can earn on them. Sounds good.

The website
The website is great looking, indeed: clean UI, simple navigation, useful categories, and so on. Nothing to say about it.

The client
The best part is the client, from which you can get and update your favorite packs with no effort. Just cool.
Imagine: get your favorite mod or texture pack right in the game, and always updated, with just one click. Amazing.

The reality - from an author's perspective
Revenue on the CurseForge website is measured in points. What are points?
The Rewards Program FAQ section doesn't tell us much about that. Meh.
On CurseForge, you get 0,05$ per 1 point. From my stats, I think it's about 1000 downloads (for now, I got 9 points out of 955 downloads).
On Adf.ly (which is not that good), you get (from the US) 6,50$ per 1000 downloads.
On Shorte.st, you get (from the US) 14,65$ per 1000 downloads.
On Uplod.it, you get (from the US UK CA and Australia) from 22$ to 27$ per 1000 downloads.

Ok. Let's be fair: 0,05$ for 1000 downloads it's not so much. Compared to other services, is even less.

The conclusion
CurseForge provides an interesting way of getting updated mods and other add-ons for your favorite games, so from a user's perspective is cool indeed. If you're an author and you want to earn something from your mods or texture packs, well, considered the rates, it's your choice.
From a W.I.P. texture pack, I got almost 10 points in less than a month, with no advertising.