The co-op ending was really bad.
 
I've played the single too,and i hated it that way too,it was really good game though.

I just beat the game as well, and while the ending wasn't the best ever it's definantly better then most Clancy games I've played, since the message wasn't all "AMMERRKKIIAAAA!".
 
I do hope they let Sam just continue to live with his daughter though after getting Vic out. As it's been said on the podcast, it's really time to let him go. If anything, have him be the "father" figure of a whole new breed of Splinter Cells or something.

After experiencing both endings,  I can honestly say I didn't like either. In my first playthrough I wanted Fisher to take the high moral ground so I spared Reed, only to have that wiped away by Grim. Bleh I say. Bleh.
 
Also, I saw the co-op ending from a mile away. I did enjoy the final-final mission though, rad.

Dude! I knew she was going to kill him if Sam didn't shoot him in the head. The game doesn't have very good surprises. I'll see that I guess once I beat it again on hard. Personally after beating it in one sit through last night. I really didn't feel like the game as a whole was very special whatsoever. I wish it was. It just felt so similar to a lot of games I've already played once before. And you can argue that for a lot of games, but, this just wasn't right. I did like the game though. I'm not saying it was bad. Just, not right how it seemed easily comparable to other games like Uncharted 2 or something and less like its predecessors. I think I would have liked it more if they had just made it like the other ones, just, faster paced maybe. The change of being into action was actually kind of nice. The one stage you had to be sneaky at the beginning of it was the worst to me personally I also wish you had actually been in the Third Echelon headquarters in another game. it would have made it better.    

The Reed Dilemma reminds me of the 'To Shoot Lambert' situation in DblAgent and how it recon'd my choice. Not cool brah.

I thought the choice was redundant too, but I see it a little differently; I don't see why Sam would spare him, or why anyone would for that matter. Sam has been killing people for years most of whom did far less than what Reed had done.
 
Take Reeds goons for instance, he drops them without even thinking. Why would he even second guess killing the man who not only tried to kill the president but had also been the cause of Sam's pain for the last three years?
 
I did both actions, shooting him first, but it seemed to me that "sparing" him what the developers prefered; you get more dialog and Sam seems to more satisfied with that outcome.
 
As for the Co-Op ending, I thought that while the story was a bit obvious and cheesy, the actual gameplay was fantasic.