While I am a huge fan of the 2510 and not that big of a fan of the 5600, I would disagree that the 5600 requires that much more maintenance. I worked with Pentair on the release of the 2510 and had one of the prototype valves in my house, working with both valves in heavy commercial applications, both valves were typically good for about 5-10 years in heavy use applications. Very similar in capability and performance. The 5600 econominder has had many issues with the 24 v motor, they did not last for decades like the 110 volt motors did. The 2510 almost never blows a motor since it is basically an industrial motor, completely overbuilt for the application. The 2510 had many issues with the neck o-ring collar, but that appears to have been corrected many years ago as I rarely sell this replacement part anymore. For residential applications I would definitely chose the 2510 over the 5600, but in all reality, the 5800 has really proven itself to be a great, reasonably priced replacement to both. The Clack valves are also excellent. I would say both of these valves surpass the 2510 unless you are looking for an 80's electromechanical non electronic design. Since the boards on the 5800 take about 10 seconds to replace should a problem ever occur, they are readily available and very low cost, not sure that it is that strong of an argument anymore.
So long as you stay away from the plethora of counterfeit and knockoff valves, stick with a real Fleck or Clack valve, you will do Ok. Also, way too many companies are putting Fake Fleck valves on junk from China. Stay away from the low cost online companies, most of these are not reputable. If the price seems to good to be true, it is probably junk.
