Wild surge is better than overchannel. Do some math and it should be clear. A psion with 3 wild surge is just plain awesome. Your psion has a dinky d4 HD and overchannel deals 1d8-5d8 of damage 100% of the time. Wild surge provides the PP and only has a chance (a low one that you can control) to become dazed. And even the there are ways around it.
It's amazing how little people know about statistics and propability.
Chance of dazing is NOT dependant on ML or wilder level, it is dependant on the level of wild surge you choose to use. So as a level 17 wilder I could just select to surge for +3 and risk a 15% chance of ennervation.
partially true. for one thing, the anarchistic initiate is awesome. wild surge's enervation is based off of wilder level, which you do not have. therefore, wilders can suck it.
but still, you underestimate overchannel. you can use it at will. add on talented, and you take no damage from level 1-3 powers(which, since this is psionics, is always useful). this means you get to always ramp up that energy ray, crystal shot, energy stun or swarm of crystals. very handy.
secondly, when you get to the higher levels, minor amounts of hp damage tend to be irrelevant. if you have someone in the party with infinite healing, or persisting vigorous circle, it boosts your buffing capabilties. plus, a few d8's don't matter if it means the battle is over quicker. that +1 to the save DC of a death urge can turn the tide of a battle.
really though, what is the excuse for not having both?