Keys easier, BUT.. more potential to get defrauded too.. ("it doesn't work" = "I gave it to friend")

GreenManGaming and GamersGate seem very reliable though.

Steam gifts aren't really much more of a hassle if you send them directly by mail, and it's much easier to proof to support that you delivered the gift in case you get a winner that doesn't mark it received. Also you can reroll while being completely sure that the gift is still valid, while if you want to reroll after sending the key, you can't be completely sure it isn't used.

Myself if it's an expensive game I'd rather send a gift - even if it is a hassle it can be tracked, etc.

If you are buying keys you can go with the cheapest site - but they may well be an unauthorised key reseller and maybe not 100% trustworthy. Or you could stick to authorised distributers like GMG - but keep in mind they sometimes give out region locked keys without informing you of the fact.

And also make sure that the keys are for Steam and not for some other form of DRM.

And most importantly - thanks for the kitties!

Keys

If I buy a game on Steam I send a gift, if I buy the game somewhere else I send a key.
If I buy it on steam or not depends on the price.
So I prefer whatever is cheaper xD

GreenManGaming with its USD pricing and discount voucher often beats the Norwegian pricing of Steam, so it also matters where you live, and what prices you see on the various pages (on the other hand, Bundle Stars and Humble Bundle show EUR prices for me, and they can not compete with the local Steam prices).

GIFTS

(for everything that has been bought for 5$+)

Ever wondered why Games in "Steam-Gift-Containers" are exclusively available directly on Steam?

steamstores USP: unique selling point

Steam-Gifts

are safer to store and transfer, since the game is stored in that "Container" in some account
as an item you can check up on it - which can't dissapear, be used, get lost, be messed up for no reason

while

Keys

are plain TEXT that will likely be stored on multiple places Mail,txt, word, whatever ... -> NOT SAFE
if its used by -> its still remains unless you remove it; if you give (copy-paste) it and you were the only person to see it,
your source might have used/messed/miss-copied the key, maybe not even on purpose and you DON'T KNOW
in case its used, duplicated, not row ...

Keys boil down to trust and trust is bad, for digital games that shouldn't be wasted much of a thought on
(so props to decent Bundle-Sites that used/use at least some viewing protection for the Keys - humble/indiegala ...)

to sum up:

• there is no reason, that Games in KEYS cant be turned into Steam-Gifts
• there is no reason, you can't see which account used the Key (like in Desura)
• there is no reason, you can't even check on Keys whether their VALID OR NOT (how incredibly dumb is that)
• there is no reason, yer favorite shoppe for Steam-Games couldn't send you chop-chop your Steam-Gift - its 2015 ...
  "amateurs" have done that for years (dispenser.tf / bots / real people whatever)
• ... you'd have to befriend someone to send a gift (you don't have to anyway *send to a mail, but its done automatically)

but

greed of vulve,

losing one of their USP's which is - their shit sells "most legit&safe" in steam-gift containers, and every somewhat
"seasoned steam-derping-user" knows those are somewhat safe and offer more control over your digital purchases
(thus making them also more expensive - see trades, steamstore-offers)

don't care much myself about the safety (mine always worked as they should have)
yet that aspect obvious displeased me quite - btw. ease of use with Keys isn't an argument,
if games were worth something they wouldn't be shelled out like cheese-puffs from the super,
and be stuffed randomly portioned in ones mouth (account) lol