Of your 3 I would go with the RadCity for two reasons:
1. The Izip Brio uses the SR Suntour ATS system, the controller and battery mount for which have in the past proven unreliable in Carerra brand budget ebikes sold by Halfords in the UK (see this
UK Pedelecs forum thread)
2. Prodecotech have gone AWOL, no recent reviews, customer service concerns expressed on this forum eg see
this thread from earlier this year)
Other step-through candidates <$2k might include:
1.
Motobecane Elite eAdventure step-through eMTB model from Bikesdirect with full size 700c wheels, uses the new Shimano Steps E6100 motor, plenty of
local ebike shops service Shimano Steps motors, and at 46lb it's the lightest bike on this list.
2.
Ariel Rider C-Class uses a Dapu mid-drive and Nexus 8 IGH on a frame very similar to the RadCity Step-thru. The advantage of the IGH is you can shift gears when stopped at a light which is useful for riding in stop-go city traffic.
3.
Blix Aveny, recently upgraded to a 48v/500w geared hub motor and the ability to add a front frame-mounted rack same as the RadCity & Ariel Rider C-Class. Nice step-through bike.
4.
Schwinn Constance cruiser model from Walmart, priced same as the RadCity, uses the Bafang Max mid-drive motor, Court
reviewed it here when the Schwinn brand owner Pacific Cycle was initially pricing it too high, at 51lb it's lighter weight than the other bikes except the Motobecane. Pacific Cycle also make a cheaper made-for-Walmart step-through model called the Schwinn EC-1 which is not as comfortable or as good at going up hills as the Constance.
Of the 4 bikes I suggest, the Motobecane is a mountain bike, the Schwinn is a cruiser, and the Ariel Rider and Blix are closest to the RadCity in design. Usually it's a good idea to test ride different types of bike to find the one that fits you best, but most of these are sold online, Blix are sold though bike shops so you might find a dealer local to you where you can test ride the Aveny and have it serviced (this is a big deal). The Schwinn is sold by Walmart but they likely won't have one in store to test ride - they ship from warehouse to store and assemble the bike (for an extra $49) but only if you buy it first through them so you would need to return it if you find you don't like it. The hassle of returning a bike you buy online after assembly is a pain so check each companies returns policy carefully to find out who pays for return shipping and if there is a restocking fee, Ariel Rider is the most restrictive you pay for return shipping plus a 25% restocking fee, must be within 14 days, and the box has to be unopened which precludes assembling it for a test ride. RadPower bikes are at least
trying to expand their test ride options, or ask in a local cycling group if anyone has a RadCity you can test ride.