Both the 250 L (65g) tanks are good. The RS company does a great job with support and their tanks are well built. Both look good, are sleek and have minimal in tank hardware.
-The Red Sea Max 250 has a rear chamber for all filtration.
-Comes with a 6 bulb T5 closed hood with EZ 3 position hood.
-Includes all components. Good Sicce pumps. Skimmer is proprietary. Does the job but few other choices.
-No easy way to add a macro algae refugium.
-Actually the RSM250 CAN be customized. I have reactors, dosing pumps, ATO, Exotech pumps & more running. It can be converted to an under cabinet sump but it will cost more to do it right with the LifeReef products. Many have even tossed the T5 and installed LEDs like Radions. But if you want an in cabinet sump & LEDs from the get go, this isn't your tank.
The Reefer series is of a more traditional under cabinet sump, rimless design.
-No hood, choose your own lights.
-You choose & pay for all pumps & protein skimmer.
-The Reefer is likely to be more quiet, depending on skimmer, lights & pumps you choose. But I don't conder thee Max "loud".
The MAX250 requires no decisions on the basic set up and can be put together and running with salt water in an afternoon. It just works. The Reefer would take longer and require more decisions as you're mounting lights, connecting plumbing, choosing skimmers, etc.