I tested out both of these yesterday. What P&C said is right. The 230 is supposed to be slightly lighter, but after running them both with full tanks, the 230 certainly feels heavier during use. The 231 has a 25% larger fuel tank, but it's also supposed to use more fuel. The 230 is also somewhat lighter. As far as power, I agree with Elephant, but it was a Very slight differance. In fact, it may have just been my imagination; I wanted the 230 to be stronger. Incidently, I planned to buy one of the two, but after trying both, I decided to get a T272X, which I really like. Hope this helps.