AN refers to the angle at which the fittings come together to make the seal. they should never leak, but when they DO its because one fitting is used with a different hose and it doesnt seal well. if you're gonna use a summit fitting, use a summit hose, earls fitting, earls hose, etc.
as far as "cheaper" in my opinion you get what you pay for. the ones i ordered from jegs/summit faded QUICKLY and the ones on ebay the anodizing was removed when sprayed with WD40 when assembling them... i have have 0 problems with my earls fittings that i replaced them all with.
