A lot of people prefer big 2H crits, but I do think that Ele is the better spec for PvP since Enhance has a hard time entering melee range against most ranged PvPers and against most melee PvPers you'd rather want to wear a shield. Here's an Elemental Shaman PvP video from the vanilla days of WoW:
Part 1 Part 2. If you can't watch Part 2 because of a region thing, just download it through this
KeepVid link. I believe he is using this
30/0/21 build.
As for mana issues in long fights, that drawback is a bit overstated imo. While it's true that a Shaman's mana regeneration is crap, people tend to overlook the mana efficiency Ele Shamans have going for them. Rank 4 Lightning Bolt gets full spell damage coefficient and only costs 75 mana. With talents, that's 67.5 and every time you proc Clearcasting you can cast a max rank Lightning Bolt or Chain Lightning for free (you could macro this). And a Shaman's Lightning Bolt scales really well. The lowered cast time ensures that it's a 2 second cast with the spell damage coefficient of a 3 second spell and it gets damage and crit on top of that. With a Mana Spring totem, some minimal mana/5 gear, and the usual major mana potions and dark/demonic runes, he can keep himself going just fine spamming Rank 4 bolts. He would need a lot of spell damage gear to DPS though.