The SKS Sub40 pump I have also only attaches via a rubber grommit/seal and is useless for the job as it leaks above a pretty low pressure.
How does that Taiwan-made pump attach to the valve, and do you have a link to where it is available online?
Unfortunately I couldn't find anything on the web about this Taiwan pump, The "Brand" is MIX - Cyclone RBS but this doesn't say much, you can't find info anywhere.
The LBS I bought has no website and they are those kinds of shop that bring everything from China, HK and Taiwan so the shelfs are always full of new stuff but they do not stock volume so it desapear quickly.
I was buying a cycling short when I saw the pump by chance so I gave it a try.
I am pretty happy with the pump, the connection to the valve is directly on the thread, the oring is beefy and you do not lose any air even if you thread slowly, very good design.
It also has a very interesting design to use Presta and Shrader by selecting the small black pin in or out
The hose is well made and does not leak any air. It also comes with a rubber cap to avoid dust damaging the pump
The 2-part body is also threaded so the pump will not be opening by itself when moving (you can also fix it to the bike frame underneath the bottle cage with a very small but strong bracket but I prefare to have it on my small back pack
I am not sure about durability but the contruction is not cheap and it looks better than many branded pumps.
Although the weight is 50g+ it is smaller than the ipump and the cost is ridiculous, no brainer