Which network is better 3 mobile or tesco mobile?

So I'm in the middle of getting a new phone and have decided to get the Samsung galaxy s3 instead of the iPhone 4s but can't decide which network to get it on.
My choices are:
Tesco:… 3mobile:
All you can eat data."… 1gb data
5000 texts… 500 texts
100 mins… 500 mins
No upfront cost… £100 upfront cost
£23 a month… £25 a month

Now obviously the three contract would be cheaper but I have heard about issues with their network.
Also telco offer capped contracts so there will be no overspend and use O2 network.
So which would be better in terms of network and overall?

Added (1). Obviously the tariffs have swapped. The one that says tesco is 3 and the one that says 3mobile is tesco

I honestly think that both networks are horrible. Yes they are cheaper but that also means that customer experience is compromised. When it comes to cars for example, you don't expect to pay Ford prices and expect a Mercedes Benz experience.