That's one side of the story.
If you have deep pockets (mandatory!) and want the ultimate control of your setup, and are prepared to do the work, I doubt you could get much better than the AC stuff. Quality kit, at a price. Only you can make the call if it is worth it to you.
I'm researching, spec'ing and costing up using some AC gear for my rig. I actually enjoy all the stages above, and then the configuring and tweaking to tailor it to me. If it's done right, at the end it'll be something to be proud of, as any watercooling setup is.
The way I see it, you have this powerful pc but you still have to turn a knob or ten when you want to change from silent running to cool running? I think the system (however it's done) should do this for you, and there are other options other than AC. Also I agree a lot of information output by sensors that you don't necessarily need, but you can use, even if it's just a casual glance to see how things are.
I am planning on having an external Mo-R3 1080 rad, and 2 AC Aqualis reservoirs/USB D5 pump combos, one on the input and the other at the output of the rad. With temp sensors also in place at these 2 points I can monitor the effectiveness of the rad and control the fans of the rad based on such readings. Hell, I may even be able to run the rad passively when there is little load such as net browsing. Could I do that without sensors? Probably, but not as accurately, certainly not automatically or with the granularity I want.
With control of the pumps these can be made to ramp up or down as needed, or used to obtain that sweet spot when increased flow isn't effective any more; just increases noise and vibration. Monitor the flow to ensure its effectiveness, controlling the pumps either by flowrate or water temp or both. Do you know how much hassle it is to adjust a D5? Open case, find screwdriver, find the little red screw, turn it, wait, turn it again, etc. I'd imagine 95% of D5 owners keep their pump at one setting once it's in place.
You see how powerful control can be? I've only just scratched the surface of what can be done.
As for AC waterblocks, it's a matter of taste and aesthetics (don't think I'll be using any of them) and they do perform like all the other blocks give or take a few %.
If you have the time, money, interest and desire to build and control your system with Aqua Computer kit, don't hesitate. It'll keep you busy for sure! If you only want to watercool in the littlest time possible and willing to settle for middle of the road performance and control, then bish-bash-bosh a simpler watercooling loop in your system.
The choice and justification is yours to make.