The original design premise for the i3 was as a city commuter car where the normal commuter rarely drives more than 30 - 40 miles a day. The REx option was put in place more to address the range-anxiety of the potential buyer than turn the i3 into a true hybrid. It's a 650 BMW scooter motor that powers an electric generator, put there as an occasional-use back-up power source.
I live in Texas, and think my i3 REx is great. Below 80 degrees, I get around 60 -70 miles on electric, depending on how 'aggressive' my driving is. Get into the 90 - 100 degree days, with the AC going strong, the electric range does drop significantly (the AC not only cools the cabin, it also cools the high voltage battery pack). Great car for me - I rarely drive more than 20 miles a day. Could you use it to drive 75 - 200 miles a day? Sure - in the full AZ heat, guessing 50 miles max electric a day (maybe less), then gas up every hour or so to run with the REx. Would I do it? No. As much as I like my i3, I'd be looking for either an EV with at least 200 miles range like the new Chevy Bolt (knowing on some days I'd still have to stop and charge for an hour or so over lunch), or a solid 'real' hybrid. And do you have the option of installing a level two charge station at home? With an EV and the miles you drive - a necessity. Trying to keep a high-mile EV 'fueled' using the current public charging infrastructure will be a study in frustration.
Can you write off your car as a business expense? If so, I'd be looking at something new, which will have the biggest battery, and a service warranty that will provide a free loaner when the car is in for service. With the slow car sales due to Covid-19, there are some great new car deals to be had - 70 month financing to keep payments reasonable, and very low interest rates. Otherwise, I'd be looking at a used Prius or similar.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE