I ran B5s for almost a year. Pretty good motor,did have some problems with them at about the 6 gallon mark. Switched over to Alpha about a gallon ago and must say it is as good if not better than the B5. Time will tell. It has a stronger bottom end than the B5 and about the same if not more top. Break in is a little harder on the alpha. B5 breakin is simple and easy. Both good motors for the price your willing to spend. B5 runs best on the 2013. The alpha you have more of a pipe selection. Ive ran it with the 2013, 2035 and soon the 0801. They all work great and about the same run times. The best Ive got out of the alpha is 9 mins but it is still breaking in. The B5 is 10 mins plus right out of the box.