Yes you do slightly more damage, but you also take more damage.
Getting power crystals instead of expertise is the only good swap because it's 1:1.
I agree with the power crystals swap being good, that makes sense for any class.
I do however have to disagree that it's the only good swap. You could argue that for some classes it's better than others but I haven't see a case with any of my 50s that it didn't increase damage/healing significantly enough to drop the 110 expertise (which is a tiny amount).
My jugg's pvp gear:
My belt + bracer
Stock belt + bracer
As you can see I gain a substantial increase in str, pwr & end.
Here are the break downs. By using my belt bracer with the pve armorings I...
1. Lose 1.07 damage boost
2. Lose .71 damage reduction
3. Gain 45 force bonus power and substantial gains to melee min/max damage (scales to about a 5% increase on smash damage, much higher than the 1.07% damage boost from exptertise)
4. Gain crit chance
5. My health goes up nearly 800 points.
People ask me how I hit them so hard on my shadow. Power stacking. At a certain point (which I feel is around 1200) it's a no brainer, power > expertise.