Send a message to MuruCycles, this is right up his alley
Cheers
I'll be very honest here and say that my personal knowledge with ebikes isn't very good. However... we are in the bike industry and all that.
My suggestion would be to think
less about the actual bike brand, (though it would be nice to have the support of a credible larger brand to fall back on) and
look more at the brand of battery and electric motor that is attached to it.
My choice for battery/motor would be to stick either
Shimano or
Bosch. Both are long term (proven) brands in the world of electric bicycle motors and batteries.
So based on your three options,
Merida offers the mens style 29er with the Bosch and the ladies style with Shimano. The mens model is a proper off road bike however. While the ladies one is more for cycle paths, the shops and the occasional graded dirt road.
The
Dyson uses a Panasonic system. I'm not at all familiar with the Dyson bikes brand. And Panasonic motor/batteries, while not bad by any stretch, is just not as developed or as commonplace as say Shimano or Bosch. This bike is also running older style rim brakes. Pretty much every bike out there now (new) is now fitted with disc brakes.
Based on those three options... I'd get the ladies Merida. Nice looking bike, pricing is reasonable for what you're getting and it has a good nationwide dealer support network.
Hope that helps a little.
Wayne.