I have the MICRO8 card holder for more than 1 1/2 years in daily use and for half a year now the SD + microSD holder. I can understand the negative recessions in two articles (of because of 'not fit', 'wobbles' or even 'fall out') does not understand completely. That only thing I've noticed so far is that the labels of older holder sticking front and back out are worn. And that's because I always have the two in your pocket. Meanwhile, I have, since I have my driver's license and PersonalausweiĆ in Kerditkartenform, bought a durable carrying case for everything together.
So I can only recommend buying both tickets. Which is the right one, depends on the use. If you also need an SD card (for example, for digital camera ect.) Then the thicker SD microSD with two SD card slots and four for microSD's. I have a SD card adapter for miniSD and a MiniSD Card Adapter MicroSD slot and the second in a large SD card slot I have a super small USB microSD card reader.
So I have six microSD cards in SD + Micro SD holder, a USB reader (okay jammed only between, but fits and holds) and can use my MicroSD's also in MiniSD or normal SD card devices.