Hi brookesy & welcome to the forum
It's good that you are trying out the bikes before choosing!
My only experience is with the bikes at 50cycles I tried before I chose my bike: I was looking at an Izip too, but there was no comparison with the Liv I tried - the Liv was a far superior ride, quite a responsive "zippy" feel to the motor while laid back style at the same time, and very easy to use 3 hub-gears (can change gear when stationary too!) via a right-hand twist-grip changer
has front suspension like the sprint and a comfy saddle, not sure about the seatpost suspension but I think there is. I haven't tried a sprint so can't compare, but it compares very favourably with a cadence I tried which seemed a bit heavier with its strong build - gel-filled tyres etc? I don't know how the Liv's weight compares to a sakura, but it seems on the lighter weight side, especially with the Li battery as standard now (I think that's still right?) and in comparison with the izip & the older heavier ebikes. 15mph max though
If you haven't done so, the ezee Liv thread on this forum is worth a read for more discussion & information.
I was going to point out the powacycle/byke confusion but I see you clarified
that
I haven't tried any powacycle bikes, but I think I'd be right in saying the Liv motor is higher power than the Windsor's? (sorry guys, but I'll stand corrected if I'm wrong?) so would give more torque from a standstill and better hill climbing if you ever need it, but the windsor may possibly give more range for the same battery capacity if the motor output is less... probably not much in it though and I don't know how the LX & ezee Li batteries compare power wise, but both should give a healthy range.
Too much information?!! Depends if range is an issue for you I guess!
Hope that helps you in your choice anyhow
P.S. I chose a Torq though for similar reasons to Ian, but that's not really a bike many "ladies" would prefer I guess (again, I'll stand corrected if necessary!)!!!!
Stuart.