I've owned some Aqua C, I've also had some Deltecs, Bubble King, Euro-Reef, ASM, ATI, Tunze, Ice Cap, and a Skilter way back in the day. Currently I run a Tunze and I'm thrilled. Like all Tunze products they run forever. Their service is top notch but more importantly, no one ever really needs it. Should something ever go wrong you don't have to worry about parts as they're readily available.
I think Tunze skimmers tend to be really utilitarian and since they aren't "sexy" don't get the attention NYOS and the rest of the skimmers going down that path take. My 9410 pulls almost as much air as my old Bubble Master 200. It's an air cannon. It's also pretty bulletproof. That being said any skimmer will perform about the same as any other skimmer. I went Tunze for the reliability, parts availability and the design is pretty brilliant.