put simply...the one you prefer.
Try them all at a walk on day... ask around and have a little try on the range with them. There is no other way of finding out and randomly buying a marker may end up being an expensive mistake. Worse case scenario at a walk on... it costs you a few drinks
I love the mini...someone else will say its too small and get an axe. Then someone else will say it eats more air than an Etek so you should get one of them instead... the other guy will say you should be going Milsim and buy the Etha so you have a tourny and milsim marker in one. Someone else will say you should never play milsim and tourny markers are the only ones you should purchase... then we have WW3.
There really is no right answer to that question