I can't find much of anything about this company on the Internet.
By saying that you've "test-driven the bikes at this company before" do you mean that you've visited this company in China, or are you saying that you visited a US based retailer that sells these bikes? If you test drove the bike at a business here in the US than I would probably look elsewhere (most US e-bike and e-bike kit retailers offer a manufacturer's and/or retailer's warranty of some kind).
Meanwhile, e-bike warranties can be very "iffy" when you're dealing directly with a foreign business while living here in the US. Not all foreign companies cover the shipping costs related to component returns (which can be both very expensive and time consuming when dealing with say a company in China). Also keep in mind that, like all products, miss-use and/or abuse of an e-bike can void any warranty claims that you may have. Some companies will, rightly or wrongly, use this "miss-use/abuse" as means of not honoring any warranty that they may have offered at the time of sale (regardless of whether or not you miss-used or abused the bike).
Btw, the 70 mile range you mention sounds like a stretch to me...
Anyway, you might take a look at the E-Moto line of electric bikes (which are, iirc, sold at Sears, etc, etc).