I had a feeling of dread ever since I was presented the choice between money and revenge; knowing then that there was no way that there'd be as triumphant an ending as the GTA 3 era games. Usually, either are regarded as the 'wrong' choice against doing 'the right thing.'
I let Niko's enemy go, thinking that it'd be the right thing to do, and chose to kill Dimitri, once again being convinced that it was the right(est) thing to do. I figured that it'd be Roman or Mallorie that got it though, not Kate who pretty much made the money out to be the asshole move.
The last mission frustrated the hell out of me but was a hollywood spectacular, par for course for the GTA games. Funny thing was, I had managed to get on the helicopter on the first attempt, but I was so caught up in the moment I ended up crashing the helicopter into the river instead of using the right trigger. After that I had to redo that whole thing 3 times before I nailed the jump and got on. I got hit by that rocket and was about to throw a fit until the cutscene kicked in.
It's still sorta sad that there's no ultimate ending to turn to, but I guess I should be happy. I was expecting the darker story direction to get Niko killed.