OEM inks are definitely better than Precision Colors inks. I use both. With one Pro 100 and a Pro 1000 printer.

With the Pro 1000 printer, they only make half of the colors; the other half they sell are OEM because they can't match them.

"The only scientific tests of which I'm aware are Aardenburg's test #326 of Precision Colors PC42 inks in a Canon Pro-100 on Canon Pro Luster, which resulted in fade ratings of 1.2 (worst 10%) and 2.3 (average) megalux-hours. The same methodology (AFAIK) was used in Aardenburg test #304 with Canon inks in a Canon Pro-100 on Canon Pro Luster, which resulted in fade ratings of 57 (same for worst 10% and average) megalux-hours. In other words, Aardenburg found that when exposed to light, the Precision Colors PC42 inks faded 25x to 48x as fast as Canon inks for printing with a Pro-100 on Canon Pro Luster paper."

This is better?

I use Precision Colors because it's cheaper; and because for the most part I'm not printing for prosperity but to pop a print up on the wall for a while (until the next comes along). The rest of the time, the prints are stored and not subject to light. If I want a print that lasts, I'll use the OEM ink, or send it off to a printer to print on archive paper with archival ink. I don't want the expense of maintaining a system for those kinds of prints; I don't do them often enough.