If I remember correctly the R2 uses bronze bushings that need to be lubricated over time and add mass to the toolhead. The R2 is a bowden setup so it can tolerate the extra mass. The TAZ being a direct drive needs to keep the mass as low as possible.
I agree that there is too much slop in the stock TAZ, but it seems like most people are able to tune that slop out. I was not able to, hence the upgrade to bearings. Saying that, my prints looked ok at 100mm/sec stock, but I wanted higher accelerations for sharper ABS corners. After the upgrade I can run 100mm/sec, 1700 mm/sec/sec acceleration at 0.14mm layer heights and get stellar prints.
I find each printer in this price range has its pros and cons. You have to choose the one that best fits your requirements and make it work for you.
So far I am impressed with the quality of the TAZ and how easy it has been to tighten it up in the few places it was not perfect for my needs. There are faster, more accurate, more turn key printers out there, but none of them have the open source hardware approach, build volume, ease of modifications, toolhead options, active community, and support team that backs up the TAZ.
All this is my opinion which is worth what you paid for it.