This is a discussion that kinda needs to get to the nitty gritty of what you consider comparable. There are a lot of ways to get the same general functionality as the Pika system, but Pika's approach is fairly unique.
So...what are your criteria?
You want a DC coupled system like Pika and SolarEdge? Outback, like PV_noob said, or SMA Sunny Island perhaps, but I think you'll find Pika and SolarEdge are the most out in front in this category.
You want a system that's scalable up to higher power like Pika? Tesla Powerwall is the other one that can do that. (It can scale higher).
Want to be able to add batteries to any solar system? Probably you need an AC coupled approach. Lots of different options, some good, some not.
Or name some other specific criteria and we can discuss further.
