I prefer wracks that are enclosed with glass doors that are either tinted or made of stained glass. My main rack is a Savinelli Burlwood that holds 36 pipes. I have never had an issue with it in over 20 years. The sun will discolor Ebonite/vulcanite stems fairly easy and de oxidizing them is a pain in the ass. The sun can also mess with the staining on the pipe if stored in direct sunlight.
I have a 15 count rack with glass doors that keeps the sun out and it is sitting empty since I redid my pipe collection. I am in not in the market to sell it unless of course you "made me an offer I couldn't refuse". Or if you left a horses head in my bed.
Seriously, I have 6 or so of the cheaper round racks that are good for my largest pipes. Only one is in use as I sold over 60 pipes so they collect dust in a cabinet somewhere.
I am lucky that in my living room where my pipes are, all the glass doors are well tinted since I live in Florida, but I still wouldn't put my best pipes in those racks with no glass.
I think you should do your due diligence and based on the type of pipes you own and how far you are into the hobby, a custom made rack may work best. If you think you only need a 15 count rack, guess again. That 15 count will get filled up quite quickly. I would also make sure to get a wrack makers references and I would get three quotes at least before purchasing. One more thing, some racks can only fit medium to small pipes, leaving your larger pipes in the cold. If you work with a custom maker, make sure you discuss that issue and maybe send him one of your largest pipes as guide for him.
I forgot to mention, I would never buy a rack from anywhere but the U.S. I wouldn't trust any Chinese rack as you have no idea what kind of noxious wood they may use. Call me a homer, but I always try to buy American even if I have to pay a bit more.