I have some micro cameras that dont like fast cards ( Class 10 ) , but they work well with class 4 cards or slower .. ( Thats life )
Im currently running a 8gig Class 10 in my double din , and can boot to any of 3 different IGO versions on the card .
I cant speak for anyone else , but generally faster is better ...
In this case it may not be , but has a fast card been tried ?
Anyhow , Im going to order the fastest card I can find soon , so far I have 48mb p/s ..
Im not sure how fast micro SD can be , regular SD cards can do 75mb p/s or faster ..
Micro SD cards are fickle at best , and my experience is - just get the best your money will buy .
Going cheap unbranded cards has resulted in too many card failures for me , even in something as simple as a MP3 player .
But hey , to each their own - its a big planet .