What is the best community builder system?

What do you mean Community Builder system?

IMO, I think this component will fit nicely on my website.

CB is quite enough completed but sometimes it looks dated. I don't like I have to use CB login only...

Jomsoc is a fresh project but it's not for little and basic project communities, expansive and any dedicated extensions are commercial too.

Other communities extensions are not as versatility and expandable as I would wish.

I would highly recommend Jomsocial especially now it's compatible with Joomla 1.6 It has just about everything you need and I have it on 2 of my sites. There support is also very good!