Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws
I'm a fan of Aqualisa's, admittedly they are expensive but I think they're worth it. Aqualisa's tech support and customer service is top notch too.
I fit lots of Mira jumps every week and for the price of an 8.5kw £95 plus vat superb shower never any issues
Reply to the thread, titled "best electric shower." which is posted in Showers and Wetrooms Advice on Plumbers Forums.
We recommend City Plumbing Supplies, BES, and Plumbing Superstore for all plumbing supplies.