Not a single wifi consumer vendor have any say on those features. it is one hundred percent done on the closed OS in the radio chip.
your expensive ubiquiti/oanda/cisco have the same mimo/beanforming performance as any opensource/clone using the same wifi radio chipset.
the consumer facing OS just flip a bit somewhere in the configuration flash. granted, knowledge of the right bit to flip mighty be missing on the opensource still, but there's no magic happening in ubiquity owned code.
uniquity is extra shaddy as they buy off the shelf components but demand custom labeling to look like it's their custom silicon. it's not. uniquity is the matress store of wifi.
They're not - I have no idea about the hardware itself, but what makes Ubiquiti so popular is the software integration layer. Their stuff Just Works even for incredibly complex and large installations while still being easy to configure.
Interestingly, this is also something MikroTik isn't very good at - their long-range wifi is nice, but their consumer wifi used to be stuck at 2x2 and basically worse than cheap Asus "wifi router" which is somewhat embarrassing.
For switches, if you want fast, for small installation it is hard to beat the Mikrotik 4xSFP+ 10G switch for $150.