Why is my 3G on my iPhone 4S bad?

Basically, I have a iPhone 4S on Vodafone pay monthly, unlimited everything. I barely ever get 3G, most of the time it's the 'o'. A few of my friends have the 4s and when I'm with them they can get 3G easily but my phone doesn't seem to find it? Why can't I find 3G all the time like my friends do? I live in a big town so this probably has nothing to do with the towers.

Maybe its because everyone is changing to 4g or maybe it's just bad internet conection, if its neither of those would speak to vodafone they should be able to sort out the problem

I also have a 4s but I have 4G whenever I don't have Wi-Fi. I used to have 3G but when I got the IOS6 update it gave me 4G. I don't know why your phone is so slow. Try to get it fixed at an Apple Store.

I had your same problem, then i found out that the my iPhone's antenna didn't work properly because it fell down and the antenna got damage.

I think, your phone has a hardware defect. Go to your service provider and exchange for a new one.

I've never heard of Vodafone, get a bigger name cell network

If you take it in to a store they'll assess it. It's a bit trial and error so they'll do a SIM change first, if that doesn't work they'll suggest that (if it's less than 12 months old) you take it to the Apple store, if it's more than 12 months they'll send it away for repair for you.

Go to your settings, General, Reset, Reset Network Settings. If that doesn't improve anything in the next few days go to a store for SIM change.