Yes! When we bought SV Watermelon it had electronic sensors, but they didn't work. Peter was hesitant to replace it because they seem to go bad all the time.
When he heard about Tank Tender he figured it was worth a try. We used it for 15 years and it never let us down. it is simple, pretty easy to install, and very easy to use. You have to calibrate it (and that's how I discovered that one of our water tanks held 25 gallons, not the 50 gallons we had been told), and I think that every few years it's worth it to clean everything and recalibrate it, but it worked for us. We had that 4 tank one with the four buttons.
The electronic gauges on MV Watermelon are also terribly inaccurate, so I think it's time for us to bite the bullet and go with what we know works.