As a giffgaff user I would like to present my review of this network. Basically they are a PAYG phone sim provider, they do not do contracts, they do not sell phones but they do provide the user with a way of using their phone which is unique to the individual.
So what's the difference between PAYG and a contract? With a contract you may get the newest all singing, does everything mobile phone with a set amount of calls, text and mobile internet for a set monthly price which depends on what phone you opt for can be up to a 24 month contract. With PAYG (pay as you go), if you already have a phone, you get a sim and many contract users are switching to PAYG sims because they are probably cheaper to use.
So why did I choose giffgaff? Call charges, simple as that, I was with another company and their charges were more expensive, so I moved. As a light phone user this was the best option for me, they also provide options for the heavy user and the internet user which is great because I want to use my phone, my way, not the phone companies way with a contract.
Obviously you want a good signal or cheap call do not mean anything, I had no problems at all but I should not be surprised as they use the O2 network which I did not know when I first joined giffgaff and since the O2 signal in my area is spot on I'm a happy chappy.
I also wanted to keep my original phone number from my previous network, again no problem, just get a PAC code from your current provider and submit to giffgaff via their web-page and that's it.
When you activate your sim you will need to add £ 10 to your account, this can be done very easily online and I have had a problem with this, you also get a maximum of three month free calls to other giffgaffers every time you top up . You can also buy vouchers and top up via your phone.
I am very happy with this company and have no hesitation in recommending them, but some users may not like the using their credit card online to top up, although you can use vouchers which can be purchased at most post offices, you will still need to go online to activate your voucher or use your mobile phone to call in the voucher code which is not a problem, but for some users may be a bit fiddly.
Customer services is also handled by the giffgaff website via an agent, this helps keep costs down, again this works fine for me, but I suspect some people would rather speak to a customer service representative.
Conclusion
As a light phone user, giffgaff is perfect for me, I get cheap calls and text, I do not use the internet much on my phone and it suits me. They will also cater for the heavy users with transactions for heavy call and text users. They also have a sim for internet users and there are no contracts, you just pay for what you use. Some people may be put off with topping up online and having to contact customer services online.