1 -
I believe only upto 64GB is supported but I'm not 100% on that.
All (quality) brands should work.
SanDisk, Sony, Kingston etc even produce specific flash drives which have both a full sized USB and a micro USB.
http://www.sandisk.co.uk/products/usb/dualdrive/
http://www.sony.net/Products/memorycard/en_as/usbsa/index.html
http://www.kingston.com/datasheets/DTDUO3_en.pdf
2-
The Samsung site states that is supports upto 32GB MicroSD, it doesn't mention Class. I would try a class 10.
One other thing, you said you're using a micro usb adapter. Is that a OTG cable or a standard adapter?