thanks for the links, I guess from reading those topics that tcp is not worth considering.
Nope, I'm very sorry if i gave you that impression. It's all up to what you want to do. Your initial question was:
which one is bettter UDP or TCP [...]
And the answer is that they are two different things. To bring an infamous car analogy I'd illustrate it this way:
Which one is better [Korean car with 1.1 litre engine, 60hp] or [Trailer Truck 18-wheeler, 900hp]?
They both have their similarities (like being a means of transport) both they also have huge differences (like 5L/100km vs 30L/100km and 250kg cargo vs. 50000 kg cargo capacity)
Both tcp and udp are viable for gaming, and on the forums/code archives you'll find working examples of both that you can try for yourself and see what you like best. (If you're interested in TCP find some code written by Wings. I remember testing some example by him that I liked, because it worked quite well)
udp is generally faster and better response times but often requires more control code written by the developer.
Hope this helps a bit.