I offer a choice between sealed pearwood, stock bamboo and CNC machined black acrylic combs. Each comb functions well, as far as how the harp plays. The pros and cons revolve around tone, aesthetics, and ease of cleaning. The price of my custom harps is the same with each choice.
The newest addition is the black acrylic. The face is highly polished, while the rest of the outside perimeter remains as-machined for a smart looking contrast. They are basically identical to the Corian combs I discontinued a few years ago, but much less fragile when dropped. Richard Sleigh and I are having these machined at the same shop, which is local to me. Reasons you might choose this option could include durability over the long haul, very slick face, and ease of maintenance/cleaning. Due to the higher mass of the material, a harp with this comb will often sound somewhat brighter than the same harp with wood or bamboo.
My pearwood MB 1896 comb has considerable labor done by hand to make it comfortable and not be prone to swelling. The tines and corners are lightly chamfered, with a broad flat face to retain the maximum surface to seal your embouchure. The channels are heavily sealed with non-toxic polyurethane, and the face has a gloss finish. It’s best not to use alcohol on it as it may dull the finish. This comb is my personal favorite for tonal reasons.
The bamboo Crossover comb has tines with a somewhat more beveled profile, and I smooth the end corners a little. Other than minimal flattening, they don’t need any additional work to be reliable and functional.