Amazon is strongly recommended - they have the best customer service, the most careful delivery service and the best return policy. However, the cheapest store is typically GearBest or Banggood, and by paying with PayPal you still have some recourse if things go wrong.
The JGAurora Z-603S was one of the first printers that you could buy that worked well quite out of the box, with only very minimal assembly required. It has excellent print quality, and is a very reliable printer.
Released in 2014, while not a recently launched model, the printer is still good value, and the frame is very rigid. It is a good competitor to options like the genuine Prusa i3, and the FolgerTech FT5 - and you can be printing out of the box quite easily and quickly, as it comes preassembled. If you like a kit printer approach, the FT5 is possibly a better printer overall for around the same price, with the advantage that by assembling the printer yourself, you can become more familiar with the inner workings of the printer. Compared with the pre-assembled Prusa i3 the Z-603S is cheaper, but lacks many of the Prusa's clever features, like the removable bed, or auto bed levelling probe.
The Z-603S has its origins in JGAurora's 2nd generation product, the Z-603, but with significant improvements in every area. JGAurora has also made several revisions to the product since its release. In particular, early models came with poor wiring, and a half-finished motherboard design, but JGAurora significantly improved the quality of the wiring and motherboard in the second major revision.
The Z-603S has come in at least two models. The first model had a blue JGAurora motherboard marked “erwo” and cheap quality wiring. The 2nd edition of this printer featured significantly better quality wiring, and came with a new green JGAurora motherboard. Photos of the motherboards can be seen here. Apart from the higher quality of the green motherboard, there are some pinout changes on the board making the firmware incompatible between the two. Also, there was a change in the stepper drivers from the THB6128 to the THB7128 (by Sanyo) with substantially improved cooling with the addition of a very nice large heatsink!
There are only a few independant video reviews on youtube for the Z-603S:
DIY Enclosure (by DevilClarke)