KMP warbirds have scale outline and great flying characteristics. The KMP Spit is very easy to land. The CMP Spit, on the other hand, can be a real handful. Look at user reviews and flying videos of their Spitfire, Hurricane, and ME109, for instance. The later KMP warbirds come with air retracts, designed by YT International, and are made by ESM.

CMP, Nitro, Raiden warbirds are designed by a less competent designer and made by another factory. Look at the outline of the Spit and the FW190. They don't look right. They also don't come with retracts. You get what you pay for.