I have been going back and forth on this myself. I would like to move my WAVs to the back wall and put either MP40s or Gyres on the end to add more flow to my 150 for my SPS.
My thoughts (no decision made as of yet)
MP40: Proven and reliable by pricey. I would need 2 so we are at $600 and then I would need WXM for my apex which is another 125. So out of the gate I am at $725. Other pros is small footprint in tank and less heat transfer. Massive flow.
Cons would be motor and wire on the end of the tank being a larger eye sore then a magnet backing. Cost. nondirectional flow.
Gyres: Apex module is still 125 so a wash there. A XF250 is $340 with controller and a second pump would be 160 bringing you in at 625 or roughly $100 cheaper. Pros are the large span of water movement and surge. Reverse flow (though limited in benefit) and directional
cons: CLEANING. large footprint in tank and since newer on market questions about reliability longer term.
I am personally leaning towards gyres to save costs and for the wider flow for my SPS. Both are outstanding pumps and you would not be wrong going either direction but it comes down to which do you think looks better and meets your tanks needs accounting for rockwork, livestock, ect.
I do agree with others that you would be fine with MP40s but if you went to the MP60 then the price chasim simply grows between the 2.