As I mentioned previously, it's easy to gimp one's character, which can be a result of selecting powers with poor synergy, or just simply selecting poor powers. Offensive passive powers, as a whole, simply leave much to be desired, and there is little reason to take them over Defensive passive abilities. This has been a longstanding issue dating back to beta, and remains true today. Many individual powers simply under or over perform by a large margin when compared to similar powers. A good example would be the various high tier martial arts burst damage powers such as Dragons Bite, Dragon Kick, etc. These powers have a charge up time, and a cool down, yet their damage is sub par when compared to say Gauntlet Chainsaw from Power Armor which is a Tier One (low barrier to entry) power. In PvE, this can make the experience from one player to the next completely different, and not necessarily in a good way, except for, well, the guy with Gauntlet Chainsaw, I suppose.
Looking at PvP, that particular system in Champions Online shows some promise, if only due to the potential fun of the combat itself. The actual implementation and design feels like an afterthought, however. You definitely get the sense that PvP was implemented as part of a checklist. It's a "gotta have it on the back of the box" type of feature, as opposed to something fully developed and explored.
Like Warhammer Online, you can queue up from anywhere in the world and join instanced PvP matches, with all the action being broken up into tiers. You even get XP from PvP. As you move further through the tiers, more maps and match types open up, but with only a few of these total, it's a wonder as to why these maps and game types don't open up sooner. There simply isn't enough PvP content, and doing the same tired cage match from levels 1-20 can get boring pretty quickly.
A lack of content and repetition is a thread shared commonly between PvE and PvP in Champs. You see, Champions Online severely lacks replay value, which is probably one of the game's most problematic issues. In Champs you'll do many types of quests, ranging from simple defeat X quests, to a smattering of instances, to Open Mission styled after Warhammer Online's Public Quests, and even quests resembling City of Heroes "paper" missions. And while there is enough variety in the type of content on offer, there simply isn't enough of it.
In PvP, however, the balance issues really come to a head, as the flexibility of Champions Online lends itself well to "flavor of the month" characters. Jumping into PvP you'll soon notice you're being hit with the same few powers, knocked around with chain shotgun blasts, chain held with Taser Arrow, things like that.
The Nemesis System is one area of Champions Online that does have a decent bit of content; the problem is it's not something you can access proactively. The Nemesis system, which becomes available to players at level 25, allows you to create, name and design your own Nemesis. You'll get to choose everything from the way he looks, his personality, the types of powers he uses, and even the minions that work underneath him. The issue is, as I said, players can not proactively access this content. Instead, you are randomly ambushed by your nemesis' minions when you are out questing, and they will often drop clues that begin small story arcs which culminate in a confrontation with your nemesis. Since you can't predict when or where these minions will appear, it's not exactly a practical source of content to rely on for either leveling or just plain ol' fun. But when it is there, it's pretty good.
Crafting is an area of the game I found to be extremely fun, but your mileage may vary here. I normally hate crafting with a passion, and part of the reason I enjoy it in Champions Online is due to how accessible it is. If you're looking for Star Wars Galaxies depth, you won't find it here. However, if you enjoy crafting as a tertiary experience, Champions Online isn't so bad.
The sights and sounds of Champions Online are pretty amazing too. The graphics do well to capture the four-color comic feel the developers were going for, complete with the thick black outlining of objects and characters, though this option can be disabled. Power effects pop and have a ton of flare, especially as you rank up your abilities, and the few environments in the game look really great.
The sounds of the game are also quite good, though it is curious as to why Cryptic Studios re-used a lot of sounds from their first game City of Heroes. You'll notice everything from the sound of water splashing, to the Qularr sounding like the Vahzilok, to the blade sounds all being identical to City of Heroes. The effects that are unique are quite good, however. The music is hit-or-miss, mostly because it is so sparse. There isn't any combat music, except during boss fights, but the ambient sounds or the soundtrack in many of the game's instances are pretty fitting and don't get annoying, which is always a plus in my book. There is also a good bit of voice acting in Champions Online, and it's not only reserved for big instance fights, but many of the bosses in the overworld also have some voice work. While some may ding it as poor, I think the overall campiness of it fits the theme of the game. A great example is the Mechaniste, an apparently French Canadian supervillain with the accent to boot.