The HW100 was developed for European markets and released over 10 years ago, before the US market was anything like it is now. Over there it's field target, 0.177, 0.20 and 0.22 with power restrictions.
So power is a product of that design philosophy.
Germany has very strict laws regarding high pressure vessels so the heavy steel, relatively small cylinder and therefore lowish shot count can be explained there, although for 12-18fpe they still give plenty.
Apart from that, weihrauchs 11-12 year old pcp design still hangs with anything else on the market today.
The components are steel and built like a tank. It's modular so should something break or wear out only a small part of the gun need be replaced. The barrels are excellent and completely index-able. The reg and hammer are adjustable. Best mag/clip in the business, copied by several others now. The trigger is as good as they get and the trigger unit can be fully removed from the gun and adjusted, after which it can be replaced and off you go. Safety is also a much 'safer' design than most.
HW110 and HW44 have similar engineering, just with ballistic polymer to offset weight and make manufacturing a bit easier and less expensive.
Some of the reasons they don't get discussed much is that they don't come out with new stuff often at all, so there is typically little hype surrounding them -pretty much everything to discuss has been, on various forums, looong ago

. Being around so long, pretty much any possible issue has either been sorted or has an easy/standard fix.
Anyway that's my take, on weihrauch at least. I have daystates and FX and my HW100 and HW44 are ever bit as good, and better in some ways.