I don't really feel like giving it back. Its so helpful. Did anyone else keep theirs?

Lock picking isn't that hard, so no...I didn't keep it.

I had no use for it, so I gave it back.

can you complete the quest and keep it at the same time? i cant remember.. anyway i gave it away, i like lock picking to b challenging for me.

As opposed to the Here Skeleton Key?

it can be useful if you can't figure out the mini game, but i rarely break more than 2 picks even on a master lock. Plus you end up with more lockpicks than you could ever use just taking them off dead bodies and chests.

I gave mine back because it's so easy to pick with regular picks and I wanted to advance the storyline.

You have to return it to the Twilight Sepulcer before you can be made Guildmaster and get that handsome black armor.

This, Plus once I found out I could not use it like http://elderscrolls.wikia.com/wiki/Mercer_Frey. I said forget it, its not worth having then.

loooooooooooooooooool

You have a gap between keeping it an holding on to it..

If you return it you get a Nightingale Role, Agent of Shadow, Subterfuge and Strife. I dont know if those are worth it for the key. Or at least right now

Which is better the Nightingale Black Armor or the Thieves Guild?

Apples and oranges. They're very different.

the Guildmaster armor is the same version Brynjolf, Delvin and Mercer wear. I prefer it over the nightingale one.

Yea but with the Nightingale Armor you get a whole set, with the Thieves guild you can only get one piece in exchange for your old gear. I would have to say a complete set of Nightingale would be better.

The Guildmaster set is distinct from the Thieve's Guild.

I kept as it suited my characters RP, good-guy thief (kind of) corrupted by a deadric relic. Returned it on a separate character mainly just to compete the quest line though.

As Sam said, they are different. If you're planning on lots of breaking-and-entering activities, the Thieve's Guild armor is better. If you're planning on a lot of stalking and killing activities, the Nightengale armor is better. I have both; I wear the Nightengale armor for general adventuring, sometimes replacing the hood with http://elderscrolls.wikia.com/wiki/Krosis_%28Mask%29 when a particular quest or encounter justifies doing so. I wear the Thieve's Guild armor when a quest clearly requires lots of pickpocketing, lockpicking, and carrying off loot.

And regarding your original question, I returned the Skeleton Key. Picking locks isn't particularly difficult, and gaining skill at doing it is part of the intended game play.

Kept it? I've never even had it in my inventory.

Not even after 2750 hrs and 32 characters. I just cannot bring myself to play a stinking thief.

So you can get a whole set of armor, cause the book is telling me you can only exchange one item for your set they gave you.

You get a whole set of Thieve's Guild armor. After getting a few quests into the Thieve's Guild quest line, you can excange one piece of it for an improved version. You still have a set of Thieve's Guild armor, but now with one piece that is better than it originally was. Later on, if you complete all the quests and become master of the guild, you get a set of http://elderscrolls.wikia.com/wiki/Guild_Master%27s_Armor_Set, which is significantly better than the regular Thieve's Guild armor (including whichever piece you had improved).