I have this rack on two bikes. The disc version on my Felt hybrid (though it doesn't have disc brakes - it's what they had in stock), and the regular version on my 2010 Kona Jake. I haven't yet used my panniers on the Jake, but it looks like I'll have enough room for my heels. My chainstays are only 0.5cm shorter on the Jake than on the Felt, and I'm fine on the Felt.

I have Axiom Seymour panniers. They're ok. Not waterproof, and the mounting system is not robust. If they work for you, they work, but there isn't really any adjustment possible. I would recommend going with waterproof panniers that have a robust mounting system, if you can afford them.