Who is best? SS3 or SS4?

SS3 is better. SS4 has worse game level design.

SS3 is far better

SS3 no doubt

I like them both, but prefer SS3 for its fewer NPCs and more traditional single player focus.

Vanilla of Fusion ?

Actually, get SS3 for Fusion and SS4, get the texture streaming fix to 4 and get busy killing :3 !

Strongly getting both Fusion and SS4. Both of them are good in some aspects.

3 is just egypt the whole way through while using assets from a scrapped game. 4 is way better.

In my opinion, SS4 is much better, than SS3. Better music, better locations, MUCH more enemies. It just feels FUN to play :)

SS3

I vote for SS3.

Serious sam 3 easily.

SS3 with BFE Enhanced mod.

SS4 better

4

SS4 has better music, and lets face it music is half the game while fighting hordes of baddies, just like that.