In principle, the geared motors should be OK. I don't know this seller. The reviews look a bit suspect, but they might have been translated from Russian to english by a Chinese person, so possibly OK. They offer options and add-ons, but I don't see a system for selecting them, i.e. How do you choose the colour display?
The controllers are listed as 36v/48v. Both the 250w and 350w motors are 270 rpm, but it says that the 350w one makes 33% more torque. That's impossible if they both have a 14A controller and run at the same voltage, so it might be that the 250w kit is for 36v and the 350w one for 48v. Speed depends on voltage, so when it says 270 rpm (20 mph), is that at 36v or 48v? RPM is meaningless without saying the voltage.
Before you order, make sure that you understand the battery requirements. you can use just about any battery at 14A. The 500w kit would require a premium battery with a high discharge rate and the others need the best batteries. Avoid the gearless motors unless you know about how they perform and their battery requirements.
Only the 250w kit is legal.