Even if the calipers are remanufactured from an OEM unit, the seals might be of inferior quality.
I went through this debate a few weeks back, wondering whether I should simply grab a cardone from Kragen, or buy the Toyota rebuild kit from cdan. Cardone was ~$50 for one side, while the rebuild kit was ~$25 for both sides in the front.
I went with a cdan rebuild kit and rebuilt one side in a few hours, going very slowly and taking my sweet time. So now I'm sure it's done right and I know yet another part of my vehicle very well
BTW - the rebuild process is very simple, inexpensive, and goes fast.