Personally, I prefer the quality of Dragon Wings over Gemini. The most notable differences between the two is that DW uses plastic for the wings and tail on their models while GJ
uses metal. While, again, it is a matter of opinion, I think the detail of the DW is greater because plastic is easier to manipulate than metal to achieve better detail. Secondly, the gear on DW aircraft are removable. With each model comes gear doors and a stand, so if you choose, you can remove the gear, put the closed gear doors in, and put the aircraft on the stand for an in-flight appearance.
As far as other companies go, Herpa makes an average model, which have good attention to detail, but are not as fine as Gemini or Dragon. Skyliners has only made one aircraft, an American Eagle ERJ-145, and it is a really nice 1/400 model (there is a 1/500 version also). Jet-X makes a good plane although their manufacturing is done by Dragon, so you will see a large number of similarities between Jet-X and Dragon aircraft.
In my humble opinion, here is the top 5 ranking!!
4) Big Bird