is detain worth it?

 I trying to make some demacia decks and since a get a detain from a chest i put it on all my decks but is it worth the slot? is the only removal that  my OP can  revive the unit, besides maybe i should use better removal like noxian guile or venge what you guys think , is it good? bad? one off or more?

It's great if you need to remove a strong attacker and prepare for your own game-ending attack the next round. There's also the nice side effect that, even if the unit eventually gets freed, Detain resets any buffs to it. So capturing a super-buffed Fiora, Kinkou Lifeblade, etc. feels super satisfying.

I'd say given the cheaper mana cost compared to Vengeance, it's a decent choice. At least I've picked it in several exploration runs and haven't regretted it (It works great in an all-or-nothing Fiora deck since your game is essentially over if Fiora is killed, anyway).

It depends on your deck. It's useless if you don't run minion protection of your own, but as long as you have ways to keep your Detainer alive it's probably the best removval in the game.

I would say its practically necessary to have at least 2 cards for unit removal in any deck, and if you have limited options Detain is serviceable.  I would never call Detain an auto-include, though--if collection size wasn't a factor, there are are probably more well-rounded options (VengenceBADCARDNAME, Will of Ionia, Thermogenic Beam) and cheaper options with a small caveat (Black Spear, Culling Strike, Noxian Guillotine) for any faction combination.  As BlueSpark says, it compares well to a 5-mana version of Vengeance with the drawback that the unit can come back.  As Nighmare says, its less powerful if you don't have durable units and/or protection spells, but even then sometimes just treating it like a fast speed stun + buff reset is enough.

It doesn't belong in every deck -- certainly not most aggro lists -- but it's amazing if your strategy is to buff one minion and protect the bajeezus out of it.

Even when that's not your plan, it's great hard "removal" in a pinch.

Also, there are some clever tricks you can do, like Detain your own unit that is about to die -- it comes back fully healed and replays any "on summon" effects. Or Detain your own frostbitten unit with something you can kill cheaply and quickly to put it back all nice and thawed.

Detain always super punishes me anytime I run a buffing braum deck.

Its a great removal card imo.

thanks for the replies guys, i focusing on piltover now so I switched  my detain for a Thermogenic Beam liking it versatility so far gonna go back for detain later, feel free to discuss the card i love to see other opinions on it.

Personally I don't rate the card. It's removal which punishes a lack of removal, and which is, in turn, punished by removal. Running an expensive Deny target which is also ruined by the opponent including cards which they really should be including in their deck is just disrepectful, in my opinion, and asking to be punished. There's also the issue of it shifting your own prioritisation with the Capture target - putting the enemy follower under one of your better allies simply makes them a bigger removal target. Putting them under a weaker ally makes it easier to negate the Capture (as generally a lower value unit will have lower health), and also stop you using them as chaff (or indeed, ever attacking with them, really).

I'm not saying it's unplayable, and if it's what you've got, sure. But in a hypothetical world where you have every card, it's never making it into a deck for me.