On my digital camera I noticed a performance decrease when I used a larger card; will this happen with the Raspberry Pi too?
What's the maximum sized SD card it can handle?
I see there is comprehensive list available from this question.
See this link for a list of compatible cards:
This is a driver issue, and hopefully it should be fixed soon. My advice is to check the list before deciding on what to buy.
Updated link: http://elinux.org/RPi_SD_cards
Performance shouldn't decrease with larger cards (I'd say the same of your camera, perhaps it's more an issue with too many files/directories - some devices don't handle that well).
The Raspberry Pi supports SDHC cards, which can have capacities up to 32GB.
This will not really happen on the Pi unless one puts loads of stuff on there.
SD cards come in five maximum speed classes:
Above 10 MB/s there are two additional classes for sustained speed. These were introduced for cards used for video recording.
A Class 4 SDHC is considered as a bare minimum. A 32 GB SDHC UHS as the maximum supported out of the box by the Pi. Larger SDXC cards require prior reformatting from exFAT to FAT32.
SD cards also come in three storage types:
In the end, no, the larger card will not be slower.