I have 3W engines im my two 3-meter 3W Votecs. One 157CSTS and one 170CS. The weight and size of them are the same, and simailar to all 150-class engines. (DA a little lighter)
My favorite is the 170. It gives me 115lb of static thrust with a 29x12 three-blader carbon. That is 21,7HP. 3W says 19,5HP on their homepage. Very satisfied with this engine. The 157 gives me 18,6HP wiht same prop. (3W: 20HP)

The DA 150 is also good. Lighter but a little less power. DA has also more reliable ignitions and better service.
I will not switch to DA anyway. I love power.