The majority of risers are built at 2 factories in China - at least for powered risers. There are a few others that exist, but use the horrifically poor, exposed capacitor designs you find on Ebay for very cheap. Generally, these two factories do a good job of producing quality risers.
Full disclosure: I run
http://buyahash.com, which sells regular length (19cm) and extended length (30cm) risers. We are getting the XL's in stock Monday if you want a fast solution to ship out. I've sold a lot of risers / used a lot, and the general failure rate of what I've dealt with is about 0.5%, give or take - pretty reliable, IMO.
But overall, "Higher quality" is hard to find, unless you're comparing the 99-cent risers on E-bay versus the more expensive ones you see for $5 - $15 on most general hashing websites like mine, Cryptocables, Cablesaurus, Hashrate, or the rest.
