I've been comparing the differences I've noticed between WoW and Champions Online. Both games are fun but here's the list of things I noticed coming from the "I played WoW for six years and just started Champions" perspective.
* WoW has two factions with multiple races on each faction. Neither faction has races from the other faction.
* Champions has only one faction and no real race concept. Characters can be made to look like different races.
* WoW has a fixed class base system.
* Champions offers arch types, like fire thrower, tech gadget dude, etc. Champions also lets you make hybrids with a mix of powers from any arch type. The down side to this is the more diverse the powers you have the less "Powerful" powers you can get. You can spread yourself out too thin.
* WoW lets you customize the base look of your character which can be hidden by the gear they obtain. Character looks are fixed and cannot be scaled or altered beyond the base body pieces. Hair and such can be changed.
* Champions lets you not only customize the basic body types but change individual body parts. Elongated arm(s), fat or thin, hooves or feet, almost anything you can imagine. You can also use a color pallet to change gear and body parts coloring.
* Both are experience based.
* WoW has a talent tree system.
* Champions has a power point system similar to talents.
* New abilities level based.
* Both games abilities scale with level.
* WoW uses a paper doll system.
* Champions uses a checker board split between offense, defense, etc.
* WoW gear changes how your character looks.
* Champions gear has no effect on how your character looks.
* Champions has a costume system where you can purchase additional costume slots with a monthly stipend of Atari points. Stipend is for subscribed users only.
* WoW's quest system was revamped in Cataclysm. The transitions between quest hubs have been smoothed out very nicely. Quests are broken in to normal in game world quests and dungeons/raid quests.
* Champions has a decent quest system. Quests flow pretty well but there are some rare points where I have encountered a "Where do I go now?" moment. That isn't as bad as it sounds because you have random NPC's run up to you now and then with a randomly generated quest in other areas that leads you to find new quest hubs usually.
* WoW's quest system can let players of vastly different levels group together. The down side is players of lower level don't get as much XP from mob kills because the higher level player drains the amount rewarded.
* Champions has a feature called side kicking. This lets two players team up and the second player's level can be adjusted higher or lower to match the party leaders. That way both player can quest together and lower level players are rewarded fully while not having overpowered help. This also lets higher level players get some help from lower levels while rewarding the lower level players with proper XP for the help.
* WoW dungeons are fixed difficulties with normal/heroic (Heroic not available on all dungeons).
* WoW dungeons are also level fixed, lower level players can't help higher levels. Higher level players can help lower but the lower level player loses experience as a penalty with mob kills.
* Champion dungeons all appear to have several difficulty modes that can be adjusted like WoW's normal/heroic. There are three to four difficulty modes to play at which gives a little more flexibility in the challenge level you can take.
* Champion dungeons benefit from the side kicking feature so players of different levels can receive the maximum reward and quest experience while balancing things out so you don't blast through with a higher level. Higher level players can be scaled down to lower levels.
Raids and Looting
* WoW raids are fixed loot rewarding limited numbers of players in the group. They're also on lockout timers.
* I've only done limited raiding in Champions with a non-maxed level character. No single group can tag a boss in open world raid encounters. From what I can tell everyone that participates and gets on the aggro list gets rewarded. The reward isn't crazy powerful but it can still be useful.
* WoW offers four basic modes of travel. Run/walk of the character, a fixed flight taxi system, ground only mounts, and flying mounts. Ground mounts start out at 20, flight at 60, and taxi as you discover other taxi hubs.
* Champions offers travel powers to hero's. This means you can fly the minute you leave the start area if you want. You can fly, bounce, ride flying objects, web sling, speed run, tunnel, etc. Normal character run/walk is also available.
Quick note, while flying has been a grumbling point in WoW for PvP, Champions offers talents your character can take which will debuff enemy players of their travel powers. So you can ground a flyer quite easily for a brief period of time if they're in the air already.
I will say this about Champions, it isn't perfect but it's really nice to be playing a game where I have full control over how the character I make looks regardless of their gear and what they're doing.
Also if I really missed one of the races from WoW I could make most of them in Champions. Forsaken (zombie parts), Trolls (monster parts), orcs (humanoid body shaping), draenie (monster parts), elves (body shaping), dwarves or gnomes (body shaping). The only thing they don't have is cow people heads even though they got the legs/feet/hands/tails for em. :/
Edit: Champions also features a built in FlagRSP for your characters. See zombie guy in previous post. :D