A Franklin motor is a Franklin motor, and that is about the best you can do. There are a lot of differences in pump ends. Some have plastic impellers, some have Stainless Steel impellers. Some have fixed stack design and some have floating stack design. I personally like the Stainless Steel impellers with the fixed stack design. Mainly because they have better horse power characteristics at low flow rates, not because they last any longer. These are made by National, Hydroflo, Unitra, Grundfos and others.
Most submersibles are built to survive an average life of about 7 years. That usually depends on how many times they cycle on and off. Any pump you choose will last longer if you keep the number of cycles reduced to a minimum. Reducing the cycling is the most important thing, not paying two to three times as much for a pump.