Another problem with NS is the fact that I bought Half-Life in 1999. The game ran fine on the computer I had at that time, a Pentium 200MHz with a 3DFX Voodoo1 card.
Now, in 2006, I install Half-Life via their new superdeluxe Steam service, only to find out the game I bought in 1999 runs like crap on a PII 400MHz, and I have yet to see any improvements to HL1 that justify the retarded performance decrease.
So even if I comply with Valve and want to use Steam, I cannot play the games I bought from them in just 6 years ago.
That justifies a serious birdflippin' to Valve. And a serious raised eyebrow to anyone who tries to tell me something positive about Valve and it's Half-Life.
And now, well, I don't think that NS and Tremulous are even competitors to the same crown, since Tremulous is free, open-source and therefore happily supports freedom, while we all know that HL1-NS is a modification, and that HL2-NS will be a modification without HL2 that will actually cost you real money.
So, comparing Tremulous to Natural Selection would be like, what, comparing Linux to Windows?