I run w/ the KO EX-1 Mars R. She is a very sweet radio. I just have too much good things to say about it. The comfort, quality, craftmanship, etc... are excellent. Plus, there are plenty of functions to really fine tune your rides.
I have used the Airtronics M8, and several other brands (JR, and Futaba) and can definitely say the the caliber of the KO products are definitely a notch above everyone else.
Not to diss any other brands (they are good in their own ways), but once you have used a KO radio, you won't want to use anything else. BTW, you mention the EX-11 Helios. Did you mean the EX-11 Presto, b/c the Helios is the EX-10?
I don't think any of the top of the line radios are better than any other. The way I see it is go feel them and find the one that fits best in your hand. For me it was the 3PK. I had the M8 and it just didn't feel good in my hand so I sold it. Did that make it a bad radio? No just not for me. It did have a few things the 3pk doesn’t but the 3pk has a few the M8 doesn’t. I would think the Ko Helios radios are the same