Another point is that one maker can turn out brilliant aircraft kits but their armour sucks or vice versa.
As many have said if you are after a specific subject, a google search often turns up the different choices of makers, review and build threads on fora. Some times you will have no choice except one maker be it good or bad that's what you have to work with.
Some build great with lots of detail, just a shame that they have mixed up their versions or sizing. Others are a pig to build, lack detail but are pretty accurate in the end result.
If you are into aircraft buy the same mark of aircraft in the same scale from as many different makers as you can be bothered and then build them all. Be prepared for a few surprises.
Plastic quality is another issue. Plastic is like wood in many ways. Some are hard, which can be a great thing others are soft, which is just as good. You just have to work them differently.
Softer plastics often deform over time while in the box unbuilt, due to heat and the like. Being softer plastic they are easier to correct with minimum effort. Hard plastic can also deform over time but the twists and bows can be much harder to correct. Does it affect the result... I don't think so. As to the pleasure of the build process......some will call it a challenge, others a pain. Some will look at the completed build and think 'that turned out nice' others will look into the wast basket and think what a load of .............