I've noticed lately in a couple threads where people were talking about push/pull setups on their radiators and they were using whatever fans they had laying around.  Seems to me that it would be best to use matched fans so that one fan isn't fighting the other for speed or pressure and they would be more complimentary in their efforts.  Is my thinking on track or does the resistance of the radiator make that a non-issue?

in my experience it depends on where its mounted and i always try to use the best static pressure fans i can afford for the build. usually some version of noctuas static pressure fans for the high end and yate loon for the low end. for front and side mounted rads i always go push. for top and rear i always go with pull. the difference is minimal but thats what i get the best air flow and temps with. not to mention its a whole lot easier to mount your rads that way.
i used to just go with el cheapo fans until i decided it was time to actually try a good static pressure rad fan. went with a bunch of noctua NF-A14 industrialPPC-2000 IP67 PWMs. couldnt be happier with these bad boys at 1000rpm(almost silent). be quiet silent wing 3s are also some really nice fans too. the bad? they are expensive. the good? they are the best and they will last forever. noctuas come with 6yr warranty.
 

I have push/pull and use Corsair fans along with a Corsair commander pro (iCUE software) because you can never have enough RGB.