Not sure about these, the idea of an all one retro gaming console that works with the geniune controllers from the console is appealing but I have heard loads of negative opinions about them. There are the common and unavoidable emulation problems like inaccurate sound and colour, which you cannot really hold against it but it does make you ask the question "would I be better off with the original console?" and the same would go for the complaints about the controllers. Controllers are hard to get right, even for the biggest companies (look at the abomination that is the Dualshock 3) and controllers designed and built on a tiny budget will always have compromises and quality issues, let alone trying to create one with a tiny budget and manufacturing price point that has to work for several different consoles! You can understand why they are not quite right as its a really ambitious thing to try and do. Then there are the horror stories about the build quality.
Verified purchase Amazon customer reviews always hover around the middle mark with frequent complaints about the reliability of the consoles, complaints about having to repeatedly return them and loads of complaints about DoA devices and physically broken upon delivery that wasn't caused during shipping. There where even some comments I read on a gaming forum from an ex employee of a company involved with the importing of one of the earlier consoles, they had to repackage them for localisation and change things inside the package and he said that they would often arrive broken with pieces missing or detached and rattling around inside the box and huge numbers where like that. He estimated with broken devices and DoAs that looked fine as many as 1-3 where leaving the factory broken and they must have had zero QA at all, the company he worked for didn't help either with poor handling practices and staff that where unprofessional and rough. Consoles that had been returned either from the seller or the customer where often mixed up with outgoing goods again, sometimes even on purpose as most of the repackaging was already done on them and it allowed charge hands and supervisors to bulk up the volume of work they appeared to have done to get the PRP bonuses.
Like anything "exposed" by ex employees you have to take it with a pinch of salt but as it fitted the common complaints of people that bought them it was fairly convincing, the description of how things operated on the shop floor of the company where convincing too as I worked in the same industry.
Maybe they have fixed the issues and design flaws and got a new manufacturer and method of shipping, the complaints on Amazon are still the same though. The same issues about emulation inaccuracies seem to crop up with their other products aside from the RetroN series, even the ones they don't seem to make but design for other companies (they design and make some of those all in one Sega consoles with pre installed games etc) so they issues are common to the emulation software they make.
I guess I shouldn't be harsh, they are attempting a lot on a tiny budget and they are cheap to buy and I never saw anyone saying that they couldn't get a replacement when they did have issues so they seem to honour warranties. Its far cheaper than collecting the actual consoles too, imagine how much shelf space you save buy having the one small device rather than setting up a large bunch of original consoles too.