As long as I don't do any of the transferring over activesync it all goes at a reasonable speed.
Although I only did the transfer of close to 16 gigs once (and I have no idea of the actual time it took) it seemed perfectly reasonable at the time. And the odd album takes less than a minute... always.
I recommend you pick up one of those little sandisk readers with the card.. since they're superhandy; and you'll probably get the best speed out of them.
Samsung Galaxy S III 16GB (i9300T)
Atrix 4G (d00) - AOKP - Basically broken
Kindle Fire - CM10 [sold]
AMOLED Nexus One - CM7 Nightly
Nokia N900 - Broken USB port and no warranty woo!