Here's what I went with: http://www.amazon.com/dp/B00WGXO41U/ref=twister_B00WGXO3ZW?_encoding=UTF8&psc=1

Seems to be a better price then the two you mentioned and usually includes a warranty. You can click through the sellers and find the one with a good warranty, etc. They all come from the same factory regardless of where you purchase from.

In the last few days someone posted here an analysis of all the Amazon boards - dunno if that would help. But at the cheap end of the market, it's a lottery.

The same seller has this board http://www.amazon.com/RioRand-Balancing-Electric-Scooters-Skateboard/dp/B00WGXO41U/ref=aag_m_pw_dp?ie=UTF8&m=A1GB5PAUBB3TFE with nearly 500 reviews. Are these really for that board from that seller or some kind of generic review page for all sorts of boards?

It seems like you can only get the worst model on amazon, but here's the cheapest with slow shipping!

http://smile.amazon.com/Monorover-Balancing-Scooters-Electric-Transporter/dp/B00WGXO41U/ref=sr_1_1?&ie=UTF8&qid=1437147981&sr=8-1&keywords=smart+scooter&refinements=p_85:2470955011

My son bought mine from Amazon:

http://www.amazon.com/gp/product/B00WGXO41U?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00

It took about a month to arrive and the price has dropped since he purchased it. It was $320 then and $281 now. I'm pretty happy with it so far.