Really do not try to exceed 16gb, besides there is no real reason to do that. I use Kingston and it has life-time warranty. And fortunately I still had no problems with it on my samsung.

it dont mater what micro sd card you use as long as it is not larger then 16gb,
scandisk is a good brand....i use the chepest wal-mart one.

I just got a Samsung Rant today, and am very happy with it so far. In the users manual it talks about using the correct Micro SD cards for the phone. It doesn't say which one's are the correct one's (except a comment that only cards up to 16GB have been tested on the phone) and I don't want to void my warranty. Does anyone know which cards should be safe for my phone, and should I go as far as a 16GB, or will the higher memory cards cause performance problems?