Unfortunately I can't compare to 2 or 4gb version .. .but speed with 8gb seems acceptable to me.
The compatibility charts posted at SE site generally refer to the largest card they confirmed as working at the time of the chart's publishing ... but seems not to be a limitation of the OS or the phone's hardware ... does annoy me though ...they should list it up to the max supported size! Or maybe they just don't know for sure until new cards are rolled out.
