The Steam Controller's fantastic, if you're willing to fiddle and experiment with it. If there's something about a control scheme that bothers you then chances are you can fix it or make it significantly better.
Take Helldivers for instance. Some people use the SC to emulate mouse with the crosshair/pointer for aiming but with WASD mapped to the thumbstick for smooth directional movement. I used the SC as a controller but adjusted the d-pad so it wasn't possible to press diagonals like on a 360 controller, this way making strategems much less of a problem to call down in a pinch. You can also adjust the response curve on the trackpads so 'aggressive' ramps up and maps to your movement faster, handy for twitchier games, while 'relaxed' or 'wide' is good for racing games where thumbsticks can be a little too twitchy and sensitive.
If the Steam Controller doesn't feel right 'out of the box' then you probably haven't toyed around with it enough. You get out of it what you put in, I suppose. Community configs can be a good starting point but they can also be hopelessly confusing if you don't know the game at all.