I don't know what experience you have
and I don't wear a watch
I have two decades of experience with the much more complicated brass RainSoft valves.
By comparison, the Fleck valves are simple and easy for me to work on.
Simple plug-n-play repairs are ideal for the do it yourself and save folks, but internal
control valve repair (any control valve) is not suited to the do it yourself crowd.
Sure, some can do it - but most get in trouble and frustrated. Service and repair of
water treatment equipment is best left to the professional that makes house calls.
But they aren't easy for DIYers which is where I came in here...
I started in 1987 and have been selling and servicing Autotrol, Brunner, Clack, Erie and mostly Fleck controls along with older Culligan (a Fleck valve) and some Rain Soft valves but the last 37 months, mostly Clack.
I've done that as an independent dealer with two stints as an exclusive territory dealer; one with Autotrol and one with a company using proprietary valves from Fleck. The end of 2004 I shut down my local sales and service for water treatment and mid 2005 my well pump sales and service business.
Since mid Sept. 2003 I have sold water treatment equipment over the internet, to DIYers. My experience with DIYers is much different than yours, I do not have problems with DIYers and they don't have problems with the equipment they buy from me or in doing major seal and spacer repairs when neeed. But then they aren't buying the 2510 or 5600 valves...
Also, since Jan '97 I've been answering questions in usenet news groups and on web site forums about water treatment equipment and water quality problems.
So as Gustav says, here we are. BTW, I haven't worn a watch in like 35 years.