If I want a MicroSD card (that I will use with an adapter as both an SD card and a miniSD card), what ones have the fastest transfer rates? I am topping out at 5MBps with mine.
I don’t know enough about the various brands to comment, but I’d suggest looking for a Class 10, which are rated at 10 MB/sec minimum.
If your SD drive slot interface does not have chipset or drivers capables of using the higher speed you may be wasting money. Many do not. Check before you buy and pay a premium for a high speed card.