I have a 2006 21SE with 2016 Yamaha F200 it is an excellent choice for that boat. It tops out at 37 knots and is fuel efficient at cruising speed. I also find it very quiet. However people do say that the 150 Yamaha is satisfactory, especially as the modified V hull means that you are not able to run at high speed in anything but relatively calm sea conditions. I have never run one with the 150hp.