Compare them for yourself. Each has something the others don't. I would say that the Unseen Lord's Cinder Plate is the best general purpose because of the universal resist. It's only slightly lower in damage, pierce and life.
I'd need links to both items to be certain. Assuming it's one of the robes you're asking about, the Unseen Lord's Cinder Plate looks very nice.
When evaluating gear, I'll consider Resist first, then Damage, then other factors. Both Resist and Damage are very appealing on the cinder plate. If you're at or over level 100, consider instead the top tier Darkmoor robe, which has even better Resist and Damage, and comes with a whole slew of additional, better stats.
