I have a 1953 Delta 890 bandsaw. The previous owner, who was an experienced woodworker, installed Cool Blocks, which I still use.
Have you looked at Iturra Designs? They specialize in bandsaw accessories, and have a wonderful printed catalog full of nice things for your bandsaw, plus articles with bandsaw wisdom. There is a large selection of different guides and bearings in all price ranges, including the Carter products, but also Cool Blocks, ceramic guides that don't move, and even ceramic bearings that rotate the same as other bearings. I think about replacing my bearings or guides with better ones, but the Cool Blocks work well for me and have not shown much wear, so why change? Most likely, I don't use my bandsaw nearly as much as @Quickstep
The only issue with Iturra Designs is that they are very old school. They work by phone and mail order, not the internet. Not everyone likes them, but I do. I keep mentioning it here on WoodworkingTalk because I am a satisfied customer who appreciates their selection, prices, and the printed catalog. I have bought ordinary bearings and other accessories from them. If/when I decide to upgrade or replace my guides or bearings, I will get 'em from Iturra Designs:
4636 Fulton Road
Jacksonville, Florida 32225-1332