Well the ultimate decision is yours, but lets see if I can help a little.
Mapex Meridian Birch is an 8 ply shell drum set made of Birch with an outside ply of Maple. The Birch will give you deep low tones, medium middle tones and higher high tones (so basically nice well rounded tones), and the 8 ply shells will give you a more smooth less cutting sound. Great for jazz and light rock but you might have trouble cutting through the band if you are playing rock, metal or thrash.
Mapex VX is a 9 ply shell drum set made of Basswood which will sound similar to a Mahogany shell. The Basswood will give you deep rich low tones (a little deeper than the Birch), medium middle tones and lower high tones. The 9 ply shells will give you low end smooth sound. This set would be great for jazz and blues, and would have a difficult time cutting through the band for rock and metal.
Tama Imperialstar is a 6 ply shell drum set that is made from Poplar which will sound similar to Mahogany or Birch with deep low tones, medium middle tones and medium high tones. The 6 ply shell will give you good
attack and will cut well through the band. Great for rock and metal type music.
Tama Superstar is a 6 ply shell drum set made from Basswood and will have similar tone qualities as the
Mapex VX. The 6 ply shells will give you good
attack and will cut well through the band. This set will also be good for rock and metal type music.
You will have to decide which set better suites your style and sounds the best to you because you will be the one playing them. My personal choice would be the
Tama Superstar because I like the look of the hardware, the deep tones of a Mahogany type wood and the thinner shells for more
attack.
What genre music do you play?