I'm a PWRCell owner since Oct 2020 and am happy with our 7Kw solar 18Kw PWRCell supplying our 1850sf *house (*further clarification below). Even if there wasn't a shipment delay, I would still pick Generac or similar system over Tesla. DC vs AC is a long debate. The only thing I don't care with DC is not being able to monitor my individual panels output, but I can see how each of my 3 banks are producing and that's good enough for me. The one thing I really like with PWRCell over PowerWall is that I have total control of my system. I don't have to hope that Tesla sees a hurricane approaching and makes sure the battery is fully charged. You can read more about Self Supply, Clean Backup, Priority Backup, and Island mode from Generac's site. I also have a custom Time Of Use profile for our electric company where I can take advantage of buying from the grid as needed during our EV and solar off-peak rates, but I rarely have a need to use it. While our PWRCell feeds our single breaker box, we do have 2 SMM's (Smart Monitoring Modules) to disconnect our Tesla Charger and AC if the grid goes down. We also have to watch when running our dryer and typically switch to Clean Backup to avoid draining the battery if the SoC is low on a low solar day. The 17Kw PWRCell could handle these 3 individual devices but we want to avoid discharging the battery too low. I can also set the min and absolute minimum battery levels and take advantage of more of the batteries capabilities. Our house is very efficient so the single battery cabinet is more than enough to handle the load. We also have a gas heat, gas stove and water heater so the AC, Dryer, and Charger are the 3 items we have to be concerned with during grid outage. I normally trickle charge (5A - 22A) our cars from solar. If I need a fast/higher charge I enable our TOU setting and charge off-peak.
The other benefit over Tesla is that when the grid goes down, the system will still supply the house. Unless Tesla has changed, solar has to charge the PowerWall and then it runs the house. Until the battery is charged, the solar only flows to the PowerWall and you are down until the battery can supply the house.
My real disappointment is with Generac as a company. They are as bad with their PWRCell support as they are with their gas generators. As long as you don't need them, it's great. If you have a problem, then Generac is no better than Tesla as far as getting stuff done. I had to hound them for 3 months to get a bad battery module replaced. I have an electrical background and I proved it was their module that was messed up but I still had to fight to get it replaced. The good news is that we were operating fine on 5 modules (14Kw) until I got the replacement. Level 1 support is helpful but they are limited on what they have been taught. Unless you are a dealer, you can't get to upper support. Since I proved to upper support that the module was bad, I'm no longer able to get data dumps on how my system is performing. Another thing that just shows how poor of a company Generac is. MY data, why can't I have access to it??????
As far as the cabinets & battery modules. I would spend the extra money on the outdoor rated even if you are installing in the garage/shed. The reason is that they have a wider operating temperature range. I have the original cabinet/modules and they shutdown at 40f. I had to add a small heater in my garage for the rare times when it drops to 40. The battery modules are the exact same internal battery cells. They just opened the firmware to allow you access to 85% of the full capacity vs 80% on the original modules and claim they are 5% better. Still a ripoff and they should be giving us access to at least 90%.