Some HVAC guys I've talked to say it really doesn't matter which one you go with, just that the sizing is properly done. I had a few salesmen talk up the N coil citing more surface area and less static pressure.
In order of my preferences for ease of air flow and easiest to maintain (clean):
1.) Horizontal slab coil.
2.) A coil.
3.) Z coil.
I don't buy that less static pressure with a Z coil, not sure how they came up with that. They are just throwing out terms to get you excited but it won't make a difference so esp should be the least of your worries. Note the E, stands for EXTERNAL, not internal.
External static pressure relates to air flow across an entire hvac system which directly correlates to duct design, not so much the coils as they have already been accounted for.
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