Ok, let me be clear on something, I disagree. You can spend tons of money on high end cards as pointed out by jcrick but even so - your sync speed may still not be fast enough to handle music. Hotsync speed to an SD card is determined by several factors:
1. ARM Processor speed. A T3 will sync faster than a TX given the exact same card because the T3 has the fastest processor and all of the data still goes through it. This is more critical then #2.
2. Card Speed - and this is a two way street. Some cards write faster than read although most read faster than write. And this is extremely variable.
A card reader will always be faster than a hotysnc - so if time is of the essence then spend the $20 bucks for a card reader - especially if you are going to plan on transferring music more than once to a card. Besides, then you can read other devices etc.
Also, you can use a card reader to transfer other files regardless of format or type which can still be done with CardExport but at a sacrafice of speed.
I actually use a Card Reader now as a backup for my Microsoft Money file on the PC - it's either that or write the backup to a cd everytime.