Yeah, cheap coax adapters are not worth the cost savings. You'll end up spending more on Tylenol and hair replacement products.
Spend the money once and get the good stuff. Amphenol is good, so is RFI brand. Or better yet, just put the right connector on the end of the coaxial cable. If you have the right tools, or a local shop, you can buy 90º BNC connectors that will make your life easier.