Okay, here's my take:

GOG and Steam have some game differences, so if there are games on GOG that you want and aren't on Steam or vice versa, your choice is made for you (assuming you're fine with the platform).

When it comes to indie games, games sold on both GOG and Steam, I find that bundles are better than GOG. They are of course more limited, both in choice and in availability, but most indie games do come to bundles, and they typically provide both a DRM-free copy and a Steam code, thereby covering both bases. When it comes to Humble Bundle you often also get a DRM-free Linux installer, something that's not available through either GOG or Steam. (GOG due to lack of Linux support, and Steam due to not providing an installer).

I like DRM free titles, but if the game is only available on Steam and the only "restriction" is, that I have to launch it via Steam, I'll buy it. I'm not going near any always online DRM games though. If a game is available in multiple stores, I usually buy it from GOG because I know it's DRM free and because I like the guys for taking care of the old games. There are quite a few games without any DRM on Steam, but while it's no real secret, it's not promoted either, so to rule out any doubt, I prefer GOG in those cases.

Edit: If it hasn't been liked already, there is a list of DRM free games on Steam. You can just grab the gamefolder and copy it to any directory you like. Of course you have to install it via Steam: http://www.gog.com/forum/general/list_of_drmfree_games_on_steam

No, not at all.

You need to choose what is best for you and your gaming / wallet.
GOG sell DRM-free only and no Steam keys.
Steam sell you Steam keys and no DRM-free downloaders.

also,
IndieRoyal, Humble Bundle and Shiny Loot will all sell you Steam keys, and sometimes even have DRM-free and Steam keys.
GamersGate will sell you Steam keys or DRM-free.

On thing Steam has going for is the fact that they have some classic pc games like Star Wars Dark Forces, Vampires, and Call of Duty 1 and Battlefield 2 and Id games that GOG does not have....yet.

Steam = QUANTITY
GOG = QUALITY

Or SecuRom :)
http://www.gamersgate.com/DD-DPDC/deadly-premonition-the-directors-cut
(for some DRM-free, you need to trick the downloader if you want to backup your game).

I use both. The new games i tend to buy from Steam and the older "Good old games" / "childhood memories i get from Gog - even if some of them are available on steam these days.

GOG and Steam work pretty differently to begin with so its very hard to compare them 1:1.

I am hoping GOG will eventually get (optional) autopatcher and rework these forums to have better social side of things - but only time will tell. Personally i like Steams no-fuss download and autoupdate, but some hate it with passion.

So it also depends really what kind of expectations you have as well.
I am bit puzzled by this. I mean what does being "true videogame lover(tm)" have anything to do with DRM attitude? Like arent all consoles full of just DRM games, so console players arent "true videogame lovers"?

Anyway, what is "true videogame lover" to begin with? You just buy the damn games from where ever you want and play them with the machine you like - and if you love the game, well then youre obviously doing something right. That is what games should be about right? Enjoyable way to spend time.

Personally I like to use a combination of distributors not only to oblige the "eggs in one bascket" rule, but for some additional organization.
GOG/DotEmu for oldies, Desura/Humble for indies, Steam/Origin for whatever else if needed be (like the exclusives, bargains/bundles, or gifts) has been my spiel.
GamersGate came into the mix due to some adventures I didn't care to wait for GOG to finally bring (like the Cryo games in Anuman's catalogue).
Similar case with ShinyLoot lately - the Conspiracies games made me sign up, and their clearer stance on DRM-free combined with probably one of the best search functionalities got me to stay. Hopefully they'll continue to grow, wouldn't mind them replacing GG and at least some of Steam in my mix.

They complete each other at some points. If I were stuck on an island my honest choice would be GOG.

DRM free...simple as that.
Whenever a game's on both, i'll buy on gog.
When a game is only on steam, i'll still buy on steam though. I wish there were more alternatives and more DRM free ways to get games but sometimes, there aren't.

best solution, use both atleast thats what im doing

Of course, no connection required! Trevor could grab this scenario for GOG marketing film :)

Steam is a disgusting walled-garden DRM fest that puts the user experience in the control of corporations rather than in the control of the end users themselves. No refunds even if your game doesn't work, horrible customer service (you're lucky if you get an automated email within 2 weeks), online authentication & tracking/monitoring DRM in a lot of titles, and an infuriatingly arrogant attitude from one of the most smug blowhard control-freak corporations that currently exist in the gaming industry (Valve).

GOG is DRM-free, lets users play their games without ever having to launch a third party client or home-in to an account-based authentication server, has good customer service, actually communicate with customers, has a 30-day refund guarantee if your game doesn't work, and actually treat the customer with respect (as opposed to Steam which treats the customer as just another statistic that can be shoved into a walled-garden if you dangle a few carrots in front, and your concerns will most definitely be read and then subsequently ignored), and doesn't blatantly lie as a matter of policy (i.e. Gabe saying they don't care about piracy, then spending more time, money, and resources on anti-piracy measures than any other corporation in existence, going as far as to develop an anti-piracy system for certain newer games that sends out a locked-down custom .exe file to each and every user matched only to his/her specific PC configuration... oh but they don't concern themselves with piracy issues, what a laugh).

If you respect your customers, you won't treat them like a criminal that has to prove themselves and ask for permission to play what they paid for, and you won't try to spy on and datamine your customers. CD Projekt/GOG, with their DRM-free policies, proves that they treat the customer with trust and respect.