When it comes to production, string inverters and microinverters are both very efficient – microinverters might have a slight edge with 5% more efficiency on average. But it is their ability to cope with shading
that makes a huge difference.
Shading is a great hurdle for string inverters. Every module in the string looks up to the worst one. It means that if one panel is under the shade, the performance of every module in the string drops. Usually, to minimize the effect of shading on the string, solar owners have to connect panels in parallel, or add power optimizers
to the system.
With AC modules, you won't have such a problem. Panels operate individually – each one has its own inverter. Sure, if one panel is in shade, its performance decreases, but it doesn't affect the other unshaded AC panels. Likewise, if one panel malfunctions, others don't suffer from it. Normally, you can monitor the state and performance of each AC module through your smartphone.