More on bearings over here: https://www.youtube.com/watch?v=5Dkruh8NO9E
I order at Banggood Alot! (74 orders) Mostly Quadcopter and other RC related stuff.
The bearings are not the same as the ones on Amazon, they miss the engraving shown in the Amazon Pic.
I think they are dirt cheap but not low quality, 47 out of 49 reviews were 5 star and these the bearings were individually packaged to protect against dust & dirt.
There is noticeable less wobble in the carriages and the print head.
My original bearings are very loosly fitting, I never had any real trouble except on the first layer of maximum sized objects like the http://www.thingiverse.com/thing:1385312
My first 2 benchy's came out fine, one with Flux Cura1 and the other with Simplify 3D.
I see no reason to spend more money on "Premium" bearings and I will definitely not go back to the original ones.
I think the S3D (0.15 210C) looks better and was a lot quicker but I use it all the time and tweaked the profile for my needs.
The Cura 1 (Medium 0.15 200C) is just default Flux Studio 0.8.1
Cheap Hobbyking Silver Filament