1970 Swinger 340 sending unit

Ok, who makes the best fuel tank sending unit? I have a brand new tank and sending unit and my fuel gauge never worked. All the wiring in the car is 100% new. I removed the wire plug from the sending unit and made a ground wire to ground the plug. When doing so my fuel gauge moves to the full mark leaving me to believe the sending unit is defective. I know its hit or miss with the aftermarket sending units. What's the consensus on the best one available? If I could find a good used or a nos one I'd go that route. Thanks in advance for any help and advice.