I knew engnbldr would be mentioned eventually.
I have bought several parts from him in the past. I have his "turbo" oil pump on my engine now and it kicks butt, my oil pressure is noticibly higher on the gauge than it was before, but that may have been due to my old pump having 200K on it. I have also ordered a couple of his timing chain sets now, with the metal guide, well made and I would buy it again. But, in both cases, I threw away the timing cover gaskets that came with it and bought OEM gaskets.
I know I am a fussy bastid, but I have never seen an aftermarket gasket that fit and felt as nice as the OEM ones. This includes the various knuckle seal kits you see from many vendors. They just aren't the same quality. Yeah, the cheaper aftermarket ones work "OK", but I like gaskets that fit right the first time, don't hang over, need to be trimmed, etc. The OEM set I got from Toyota was noticably better in quality, even better than the Felpro kits I've used in the past.
Same thing for seals, I only use OEM.
There, my opinion and I'm sticking to it. I'll shutup now.