They look reasonably well built for the price. The 1A single one is only 7 bucks and fine for powering lowish drain devices or overnight charging when speed isn't essential.
Anyone care to test the output to see how clean it is?
http://www.thewarehouse.co.nz/p/necessities-brand-wall-charger-1a-white/R2046451.html
http://www.thewarehouse.co.nz/p/necessities-brand-dual-usb-wall-charger-2a-white/R2117369.html
http://www.thewarehouse.co.nz/p/tech.inc-usb-wall-charger-2.4a-white/R2019597.html