This is general question on which type of valve is more reliable.
On the advice of a plumbing associate at my local HD, I soldered a "sweat type" ball valve on the 3/4" cold water supply to my hot water heater. After turning on the water I noticed a small pin hole leak in the valve itself where the two halves of the valve are threaded together. About one drip every 3-4 minutes. I plan to replace the valve.
A similar thing happened on a 1/2" sweat type ball valve on a water facet to a hose located in my garage - the valve started leaking at the threaded joint after about 6 months of service. I replaced it with a standard gate type valve.
The local HD pushes the ball valve as a better choice than the gate type valve. In my very limited experience with ball valves, both times they have failed. My question for the professional plumbers with years of experience is this. Are ball valves inherently less reliable than gate valves? Or does HD just stock cheap ball valves? What would you install on the cold water supply to a hot water heater?
Thanks in advance for your advice and opinions.