I am using Jailbroken iPhone 5s since 2 years. Nothing happened abnormal till now but, No one can give us guaranty in Jailbreaking world.
Jailbreaking is not advisable for normal iPhone users because while Jailbreaking risk is there.May be possible your iPhone faces permanent disability also.
If anything goes wrong during the procedure, anyone is not responsible for that. Jailbreaking avoid apple warranty also.
So, these are the disadvantages of Jailbreaking but advantages are more then it.After Jailbreaking you can do anything with your iPhone.you can configure the system what ever you want. After Jailbreaking no restrictions no limits. Jailbroken iPhone is best iPhone but do at your own risk.