Controllers are difficult to judge as they really depend on your tactics, party tactics, and power selection more than anything.

Druid/protector druid- The controller type druids are versatile. They can be ranged or melee depnding on desire. If you use wildshape you can also be highly damaging even up to striker level damage (though you will not have a striker nova). They have a good range of status effects and are a real boon to the party. Protectors get cantrips, summons, and a special control encounter power instead of wild shape, an extra at will, daily choice, and rituals (do note that protectors can get daily choices, wild shape, and ritual casting though feats).

Hunter-Nice damage and accuracy with proper building can be a boon to a party. They lack the stronger control effects and large AOE though. Makes a great supplement to your other controller and their nice damage can be a nice addition. Their best control is if you build them to hand out giant attack penalties (using a seeker at will, marking, psychic lock, and a mind iron Xbow). You can make hunters that won't miss except on a one.

Psion- Has great low level at wills and decent dailies. You use most of your power points on your 1st level powers which you will likely never trade so if you want a variety of powers to use this is not your class. Not as strong as a wizard (but what is?) but still good.

Invoker- the divine wizard and nearly as good. It has great powers of all types. If you don't want to play a wizard but want similar power and style the invoker is the best bet.

Seeker-can be made with decent damage. Very similar to the hunter and the two go together often. Between the two I think the Hunter has better at will usage, better encounter power for the most part, and can do more damage. The seeker has the better at will powers (in grappling spirits and the one that gives attack penalties but note that half elf hunters can get the best of both worlds), better if you do miss (which is not often) due to your inevitable arrow, and has access to dailies (not great dailies but you have them).

Wizard/mage/witch- Among the best encounter, at wills, and definitely the best dailies in the game. Best control over a wide area. Daily powers can make your DM cry.

Bladesingers- As a controller weak. Their at wills deal mostly damage and weak status effects in melee. As a striker they can be very good. Build them with str/dex focus and take fighter multiclass and the storm trooper PP and you will be a damage force. This is another class that is less a standard controller and more a combo class in this case striker (I think it is called controller only since it lacks any single class feature to be called anything else). It can be effective in a party but don't use it as a primary controller as it lacks the ability to do that in any significant way.

Binder-Tends towards soft control and is not the strongest in effects. it can control however and it surprised some in the OP trials but it has a MAJOR FLAW. That is anything it can do the original warlock can do and deal more damage. So in other words if you want to play a binder you play as a standard warlock and take the powers for the binder which makes you just as good at controlling but more damaging and you can use the awesome curse support (which can help you control even more). If you want a binder at will play a human warlock and use your human bonus at will to take your favorite power.

Wizard is best followed by the invoker. Druids are versatile and are the only likely melee controller. Hunters and seekers are more single target and thus unusual as controllers and tend towards more soft control (this leads to some calls of sucking but looking at them and their best OP experts and actual play they work fine they just are different from some expectations). Bladesingers on the other hand are at best secondary controllers that can be made into strikers. Binders are one of the few (if only) true failure in 4e as a class, not because they can't control (they do alright and the tests bore this out on the OP boards though it is mostly soft control) but that the same could be done just as well with more damage with a standard warlock (they can take the same exact powers and binders have no class features that make them better controllers).