Not in the Spirit of things

A few evenings ago I ran an instance with a fellow guildie who I've known for a long time (I actually recruited him to the guild back in the day when I was levelling my priest in Stranglethorn Vale, so a VERY long time ago). He was a shaman back then, but sometime between then and now he's rolled a priest. He's one of those players who takes a little time to understand his class, and as such gains respect from myself in what he says, because he's not just repeating parrot-fashion what he's read elsewhere, or what others have told him, without knowing why he's saying it.

Now, we were running my favouritest place in the whole world, you guessed it, Grim Batol…as it happens, we were both melting faces as it was a guild run and one of our shammies decided they wanted to try their hand at healing; THREE healing types in a party, what a waste. We obviously both did the WoW equivalent of dogs meeting at the park boundary before walkies and sniffed each other's arses… inspecting each other's gear as I was mid whisper to him saying "my god you've got a lot of spirit", he whispered the exact opposite along the lines of "where the hell is your spirit man??". This conversation carried on throughout the instance, and spilled over into an impromptu target dummy session in Org afterwards, his gear was slightly better than mine at the time, and I didn't have enough stuff with spirit on going spare to make a noticeable difference by swapping gear sets.

Now I like spirit, I really do, and I wish I could use more of it, but seriously? The only thing it's useful for is the hit it gives you if you stick two points in twisted faith (which you should) and then only up to the hit cap. The mana regen it gives you in combat is about as useful as a one-legged man in an arse kicking contest (thanks to Rowan Atkinson for that gem) due to the plethora of talents a Shadow Priest has at his disposal to regen mana. So in my view, Spirit chosen over any other stat, unless you're not hit capped, is a complete waste. Now I've spent a good few hours researching this (no just this, but stat priorities in general, I'm not quite that sad) and I can't find anything to the contrary. Am I right, and my priestly friend mistaken? Am I wrong and spirit is the best kept secret in the shadow priest's arsenal? Or is it a "you're both right, sorta" kind of answer? I'm more than happy to be proven wrong if I'm barking up the wrong tree, but I know where my spirit is, and it's firmly in the "Spirit blows" camp.