I sell Wilden Pumps so judge what I say with a bias.
Here is what I would use to evaluate which pump is better if I were you:
1. Longevity and reliability of the product. - Does it last as long as the manufacturer says it will? Ofcourse if its misapplied then that's not a fair comparison, but apples to apples which last longer in the same application.
2. Availability- How fast can I have a replacement if I need one?
3. Maintenance Simplicity- How many parts are there in the pump and how easy is it to repair.
4. Efficiency- Does one pump actually give you more bang for your buck. Air operated diaphragm pumps are not the most efficient pumps when it comes to converting Kilowatt to pumping flow and pressure. If one pump is more efficient its going to save you energy cost over the long haul.
5. Cost - compare two equivalent pumps and see which cost you more. Not just for the pump but also look at commonly replaced parts like diaphragms.
6. Simplicity- how complicated is it to use. If one pump requires additional preparation or equipment to begin use than its going to slow you down and create a hassle.
7. Improvements- This is a double edged sword. You certainly want products to get better but you don't want to be chasing obsolete models every year. Can you still get parts for old models?
8. Dimensional interchangability- Do you have options to change connection dimensions without re-piping or adding more cost. Some AOD pumps only have one piping size available for a Size pump while others have the option to allow various piping sizes on the same pump just as an option
9. Parts interchangability- Can you use the parts purchased for one pump in another one.
These points were all areas that many people feel Wilden does a better job satisfying, however, You will have to be the final judge there.
At the end of the day both companies make good pumps, the real question is who's salesman brings the donuts when they visit. Just kidding.
I hope I helped
Walter
Walter Hieber
PIB, INC. -