I'm assuming you mean the "plum" color that SOME of the OM's have. If so, that plum color comes from an imperfection in the mfg process. It IS desirable to us as collectors. But matching the plum color with NM aluminum parts hasn't been addressed as far as I've heard.
The absolute best, IMO, is a Teflon/moly bake-on. Not an option for married guys, frequently, though... Duracaot is good- I've been using it on most refins I've done in the past couple of years. Mil-spec anodizing is considered "the standard" for hard service aluminum parts; the current spec is hard coat anodize, with teflon-moly overcoat on the M-4, as I recall.
Anodizing has less build up. It is more expensive.
Teflon/Dura have tolerable buildup and reasonable cost, and are DIY without too much serious expense or effort.
Haven't played with the ceramics, but I understand that buildup is about the same as the other spray-ons, cost is about the same. Haven't heard of any significant difference (for equally prepped parts) in durability.