You do notice the cheap cables..
..when you have a long cable run. I've found this myself with HDMI cables, especially at work, connecting to displays in conference rooms. Not all are created alike. That said, If you're paying more than $5-$7 (I'm in the US) for a 6' (or 2M) HDMI, you've been taken for a ride. Personally, I find the el-cheapo Amazon branded cables work just fine.