1.6 is better in my opinion you should play it and see for your selfe

I think the main thing differences about the games, apart from complaining at the models lol, is that Conter-Strike 1.6 and Condition Zero play with a greater feeling of control while Source can feel like things just happen.

For example, people complain about the headshots in Source because they feel random.

Strangely, in regards to your thinking it takes forever to kill someone in deathmatch, I thought it was over far too quickly! I've played Goldeneye to death on the N64 and still go back to it today, and there's one subtlety in the HP system of Goldeneye that isn't in Source and it shows.

Everytime in Goldeneye you got hit and obviously your health circle would appear and drop, you actually got a small ammount of grace time (invincibility) and if you got hit in that window (it was only like half a second, maybe even less than that) the hit wouldn't count and you wouldn't be hurt. It really showed if someone had the AR33 or the RCP90's with their amazing rates of fire, yet not every shot would hurt you. This was one part of the amazing balance of Goldeneye's multiplayer, and it's not in Source. If you're getting blasted from the KF7 Soviet (which by the way fires FAR too quickly in Source), every hit will knock your HP down by loads and you won't last two seconds. 

I've found that Goldeneye Source doesn't have much skill to it - the kill will go to the person lucky or quick enough to fire first.

Not to sound too pissy about it, there were differences made from the first beta to the second release which showed definite signs of improvement and balance. Right now though, like I said before, to me it's nothing more than HL2DM in a new skin, a very pretty skin admittedly! I will be keeping my eyes out for future updates.

I'll give it a try anyway someday soon...I'm pretty hooked on TF2 though...it's such a great team game, with a hint of randomness thrown in, so I can get better at it every day, but still not know what's going to happen in a playthrough.

I am going to go with CS:S cause I did start on 1.6 but wasn't totally into FPS at the time til I started playing CoD

I play source and I got 1.6 after I had source, because some of my friends still played it. Now I got a couple friends who own source and 1.6, but they are still playing 1.6 and claiming its superiority. And I feel like I must really be missing something to not understand why they are so faithful to it.

And surprisingly this thread has been mostly pro-source

I was all ready to switch from 1.6 to Source but it turned out that the Source was worse the 1.6.. Strange but true.. The hit system in Source wasn't as accurate as in 1.6... In Source you could get an inch of the target and still hit it.. that really blew the game for a lot of 1.6 players.. So I didn't switch... and a lot of people didn't switch because of that... Gameplay wise Source is inferior to 1.6..

This is the arguement most people make against Source.  I am no Counterstrike expert, and while I find that sometimes my crosshair won't be right on my target, I still hit them.  Isn't this simply the gameplay aspect that, when in counterstrike, your bullet doesn't go directly where you're aiming unless you're sitting still and crouching?  If you're running and shooting, walking, or even standing still and recoiling, your gun becomes less under your control, and bullets stray from your crosshair.  Is this what's happening, or am I totally wrong?

I had Source first. My friend was trying to get me to start playing 1.6. He let me use one of his steam accounts that had 1.6 on it so I tried it. It was fun but I'm way better at Source. I give it to Source.
I haven't played Source in forever either because of TF2.