8gb class 4 vs (stock) 8gb class 2 micro sd

[knlmwq]

I have an 8gb class 4 micro sd card that I used with my touch pro 2. Ive had it for about 2 years. Would it be better for me to use my old class 4 micro sd card or use the micro sd card that comes stock with the evo4g??

It may be as simple as class 4 is better than class 2 but I just wanted to make sure I wasnt missing something such as since my class 4 is two years old I should go with the one that came with the evo. Thanks