I just received an RCS Phantom from a member here. It's a classic OWB Kydex "sandwich", seems very solid, great retention.
It's also....loud. The "pop" when the pistol breaks retention is much louder than my IWB holster. Makes sense when you look at it, but I'd never given it a thought.
Which got me thinking: is holster noise ever important? I suspect that in most cases it's not an issue, but I can imagine a few scenarios where the ability to draw silently would be useful.
I've never seen it discussed.