common used yagi.
owner of the antenna above, worked since 2000 with 100 watts till now
(march 2006) 225 DXCC (ssb)
Compared to a dipole the mentioned gain of 6 dB will provide an equivalent from 400 watt on a dipole to 100 watt on the 3 elements yagi.
When you improve your system you will notice a big difference between a 2 or 3 elements yagi. And still capable of being rotated by a small rotator (TV-rotator, like channel master etc.)