no there is no reson to avoid magnum. I hear they are very good. The difference between the la and fx is that the la is half the price but has less power. the fx is a performance engine while the la is a sport engine. i have a la 40 in my kadet right now and it does just fine. And if you want a cheaper but still excellent radio i would go with the 6exa from futaba. Hopefully this helps.