Iphone 4 jailbreak slow it down?

If i jailbreak my iphone 4 running ios 6.1.2 how much will it slow it down? I need advice from someone with a jailbroke iphone 4. How slow is it? Does it lag in games? And would you recommend doing it? Please i need advice before the end of the day.

Added (1). I've jailbroke my iphone 3gs last time i had one and never had any problems

Don't do it, it may seem cool but you'll be laying out money for a whole new phone cuz a warranty won't help you. Iphones can to risky to jailbreak while ipods are a better idea cuz there not your lifeline while phones tend to be.

I don't recommend jailbreaking, per se, because it voids the warranty on the phone, and you won't be able to do software installations afterwards if a new one becomes avaliable.