OS is a good range due to their parts availability and also variety in product line. Problem arises because Great Plane distributing is the only place to get them in the US and their markup is horrible especially when trying to compete with Tower Hobbies.

Thing is they have really hot .18's in the lineup that you really shouldnt pass up. They really are very popular. I dont know the markup on the .18 but they are better than stocking OS .12's.

Fantom engines are almost OS equivalents as far as pricing and performance/reliability. It may be a better option for "sport" or budget engines compared to OS because of the forementioned problem with Great Plane.

Those are the two manufacturers that I would consider if you want a very broad demographic. Novarossi/Top/Rex/RB are great for higher end race engines obviously, but a good replacement over them is Sirio. Just looking at high performance .12's, the Sirio Evo 2 is 190 versus the Nova's NSR series being in the mid to high 200's. Better value for the dollar and without sacrificing much on performance (I mean, they do hold the 1/8 ifmar title )