I play an Ogre SK, currently lvl 68. With the different hotzones, starting tutorials, and everything else, to be honest it doesn't really matter is a race/class has an XP penatly.
Iskar's are popular because of their AC and regen abilities. Trolls have nearly the same regen. The reason I chose orge was because their freaking cool looking. They've got a damn big steep with flaming hooves. How freaking scary cool is an all smoked armored ogre SK on a black flaming hooved horse??? Damn scary cool.
I did toy around with a couple of the different races as an SK and the thing that annoyed more than anything else was getting stunned when I needed/wanted to cast. As an ogre, that didn't happen. In the first 50 lvls or so that's a big deal, after that it's less important because you're either the MT or OT with others doing DPS and it's just your job to keep the baddie pissed enough to hit you.
Everyone has a different opinion as to the role of an SK. Some think tank, others think OT, others think DPS, others think waste of group space get a wizzy/zerker/monk. But if you know what you're doing, you'll be in demand as a player not as a toon.
Like all other posts about race/class, pick what you like. SK's ain't easy. Your pet will ALWAYS blow. Your spells will always lack in comparison to necros and shammys. You'll never out AC/HP a warrior, hell, maybe even a pally will out AC/HP you. A monk/zerker will out DPS you, A RANGER WILL OUT DPS you~!!!
But lets see a ranger OT in Time effectivly. Or a warrior kite. How often is a monk able to peal aggro from a cleric? As an SK you can do all of that. And do it well. A great SK is better than an average warrior. But a great warrior and SK can chain pull the hell out of a zone~!