We are currently testing a forum for techno360,but this wordpress integrated forum is breaking the theme, so we  decided to approach for a forum software.Since we cannot afford for Vbulletin, we decided to go for open source forum software’s.

Please give your valuable suggestion about below  forum software’s.
1.phpBB

2.SMF

3.punBB



If you know other good open source forum software’s , please mention their details .