BCD choice is a very personal one.
You say that you want it for a DM / trainer role - OK, so if you are diving to this level, you should have enough experience to choose your own. What you deed to do is
1) make a list of what you take underwater with you and work out how many attachment points you need, and then where you want them (then add a couple as you will always need a couple extra)
2) make a list of what features you want
3) make a list of what features you don't want
4) decide where you want your buoyancy
5) does it need to be able to take a twinset OR a single cyliner OR both? (my old scubapro does both)
6) how much lift do you need?
7) find out what is stocked locally (then you can get it serviced easily)
8) list anything special needed for the other diving you do
9) list the BCD's you have used, and what you liked about them, equally important, is what you didn't like about them
10) are there any styles that fit you better than others (eg women with 'larger' chests probably will find the Mares and Seaquest better - due to the placement of straps)
Now, from these lists it should be possible to narrow down the selection to 1 or 2 different BCD's. If there are any on this final list you haven't dived with then try and beg/borrow/steal one for a dive.
Now, you can choose the BCD that is right for you. What I have is right for ME, and is probably not right for you, and vice-versa.
Good hunting!
Jon T