I think Alfred said it well:
Originally Posted by Alfred
... Pretty much it all boils down to what particular aircraft you are looking for and who made them. ...
Let us know which aircraft you are interested in, and you will get better information on who makes the best model.
Century Wings and Hobby Master are probably the best in regards to any aircraft that they make imo, with some minor exceptions. The X-Plus/Air Commander F-4 is considered higher quality than HM's but at a higher price point. I think HM and Corgi shared their mold on a couple models including the MiG-21, so the lines can be fuzzy in some instances.