I bought a cheap one and replaced the valve with a screw dial type regulator like the CR25-100 -CR25 CR Series Brass Pressure Relief Valve, 0-100 PSI Adjustable Pressure Range
Avoid the early style all metal with a gauge and wobbly twiddly bit on the end.
If you do have or get one of these take the threaded twiddly bit out, add lots of PTFE tape so it becomes stable when you put it back in.
Another vote for SPUNDit. Works great. Can be disassembled for cleaning. Oddly, no longer listed on ebay but can be found at the maker's web site. He's very good on customer service too.