I own the Shield EZ and the M&P Bodyguard .380 ACP. Both have been solid performers for me. My wife has owned and carried an original Ruger LCP for going on ten years now and it too has been dependable. The only other .380's that I've owned in the past were a Glock 42 and a commercial Russian Makarov for which I also had a 9mm Makarov barrel that was never installed.
I would say that I've had very good luck with .380 handguns all around, but I am also not one who puts a ton of rounds through them. Each of mine only sees perhaps 100 or so rounds per year with the majority of my recreational shooting time being spent with my 9mm. I could recommend the Bodyguard as an alternative based upon my experiences alone, but there are many who report light primer strikes with it.
There are simply too many great firearms out there to waste your time on unreliable ones, so if your Shield EZ isn't up to your standards, I'd move along to something else and see how it does for you. I am convinced that different guns perform differently in different hands although there are some that are truly garbage.