Using Unity 4 / 5...
Suffice to say, it is entirely powerful and possible to create incredible games. Ori and the blind forest, Hearthstone, and plenty of AA and indie games use unity, lots of kickstarter projects.
To the chagrin of gamers, Steam has greenlit several terrible unity based games, that only use free/cheap unity store assets, namely Airplane (?) and DayZ (sic) , which are quite infamously reviewed by Jim sterling on YouTube. Enough to cloud the market for games created by any future indie dev.
Advice is plentiful, though you do have a lack of great sources to ask questions.
IMO, devs starting with unity are almost drowned in advanced features to get started from concept to prototype. Easy to learn, hard to master, easier to edit store bought prefabs than to DIY. They can become a crutch very quickly.
The unity store can be a boon and a roadblock to progress, because it doesn't always help. Starting out, it won't give you the best direction or how to code, but it will take you forward to developing a playable prototype. Sometimes within hours of starting a new project.
If you have a team, unity is going to be the source of frequent anguish, but it is still more flexible than it ever was.
the biggest hassle will more likely to be assets, and far down the road, dealing with rigid bodies, collision, raycasthit, and the PhysX implementation of mesh and mass collision.
For most devs, the initial unity workload will be around 70-80% asset creation to 20% game coding, and about 290% of the budgeted time, debugging.
A good idea is to build a prototype, get the mechanics working while the art is being developed. Once the code is in place, debug/playtesting is critical to developing assets that then can be designed, built as mesh, and imported within the prototype in a few seconds.
Character controllers are generally easy, more dynamic mechanim is able to avoid some pitfalls of the capsule collision system, and there are ways to add crouch/jump use cases with pathfinding and AI,(which is a good bit of work.)
Unity does excel at getting a walking mesh going, using mechanim to blend animation and mesh collision, and 3d art assets designed in Maya or 3dsmax, etc.
When I started with unity in 2012, it took forever to even think about how to build a menu system, until NGUI. It's improved drastically since the store was added.