While it may be a lot to take in at first, and tough to master, it is a powerful tool that the community has [thankfully] used to its full potential.
Animating is especially the most grueling part of this program, but it has high reward to it, as you can make HD videos. Of course, it needs to be re-itterated: You can't make a Valve-quality video overnight. It takes years to reach that skill level and months to finish the project. And in the defense of some that may not be used to this type of program, SFM is not what would be considered 100% user friendly.
It is like many powerful programs that carry this minor setback such as literally any adobe product. It takes a lot to learn the ins and outs of the program but once you do it, you can make amazing things.
And I will give this piece of advice to people who might be using this for posters: Pick up GIMP, Photoshop, or Paint Tool SAI, post-processing is recommended, even if you render posters in 1080p.
Overall I would totally recommend this software to anyone willing to sit down and make something and keep their focus on that project. My only complaint so far is how hard it is to launch the program sometimes. It's a shame, because even my computer with 8GB of RAM chugs a bit while using this program. But perhaps that's a tiny sacrifice I got to make for the sake of making something great.