Hmm...just looking through the wiki, I'm underwhelmed by the limited powersets and costuming choices. Obviously Champions has a big headstart, but it has a HUGE range of costume options at this point, and a pretty robust list of powersets.
The "Inspired By" option is an interesting touch though. Fun if you wanted to run a group of "2099" characters or alternate Earth, etc. Basically, you pick a major DC character, and it automatically picks your powersets, stats, personality, and even some costume options to match the "feel" of that major character. So if you want to play an expy, it makes it easier.
It'll be interesting to see how my two main CoH/Champions Online characters (Red Threat and White Devil) translate over. Red is a Soviet power armor design--all red and gold with silver and black trim, and a sort of throwback, kludgy look to his armor. Basically I made him in CoH to be the tankiest tank that ever tanked a tank. He was awesome. Modified a bit in Champions, added some alt looks that were more modernized, and traded a bit of tankability away for some ranged power armor abilities. Granted, the power armor trope is a lot more Marvel than DC. DC has always been much more into the "spandex tights" department.
White Devil was an archaeologist "ridden" by an African fire god as his vessel to fight the forces of his rival, a god of darkness. Acrobatics and fireballs and a slick white jumpsuit with red and gold flame accents. Did a later "tribal" toon of him where he was becoming more and more primal due to long-term effects of being a divine vessel. He'd make a good Vertigo character.
My biggest disappointment though, may be that I won't be able to do a decent Matter-Eater Lad expy.
Heck, I can't even talk to fish like Aquaman.