Heavy Data Users :
Giff Gaff : This is a piggyback network which runs on O2's signal. The benefits of giff gaff is that it is a payg sim card where topping up will give you minutes , texts and unlimited (totally unlimited ) data.
Now because the network run's from O2 (and anyone will tell you in the UK their 2g signal for calls and texts is legendary) the over-all signal of this smaller network is generally speaking very good.
In terms of 3g connection , again this is dependant on your area. However generally speaking the coverage is good and the unlimited data can be used for streaming and downloading.
Now after consulting the giff gaff website they say teathering is not aloud , nor is the use of the sim in a tablet. After working for a mobile company for a while I thought that perhaps the piggyback networks are maybe a little crewed.
To try this I used the sim in a motorola xoom, configured the setting and away I went tethering away and because its payg there are no charges.
This worked for 4 months until I blew 26GB in 2 weeks at which point giffgaff froze my internet service. After writting to them online they agreed to remove the bar if I dont use that kind of usage again.
Overall : Despite the fact there is no call center for giffgaff and all of it is online it is simply brilliant. Signal is great , the cost is amazing considering what you get . You can use it for tethering (even though they say you can't they never picked up on me ) and the sims can be used in a tablet.
The 3 network is a 3g only network which does give very competative deals on iphones and high end phones with their "one" plan. This gives unlimited calls/texts/data with no fair usage policy.
The tablet sim deals are also very good , 15GB for 15pound.
The problems with 3 are extreamly poor customer service (almost all of it is all off shore) im not racist however it can be very difficult when your having problems in terms of billing or when you have a problem / escalation.
The coverage of the 3 network can be hit and miss depending on where you are, obviously the advantages are good connection speeds to the internet and they claim to have the best 3g signal in the UK. Remember however that 3g has less penetration through buildings than 2g which can afffect signal indoor's.
Overall : A decent network with very good new customer deals , giving unlimited everything. After a Iphone this is probably your best network as they include tethering which almost ALWAYS makes additional charge from other networks without a bundle.
One of the 4 big UK networks orange has recenetly joined T-mobile under the "everything everywhere" banner. The company is very flexible which makes them creates a lot of plus points. Deals have become better since the introduction of the unlimited panther plans (unlimited text/calls/data). The charges they apply can be pretty high at times so you need to be a little careful how you use your phone (looks at 0845 numbers) Orange also offers the standard panther plans which include swappables , these are e.g sky sports , times , tv catch up , MTV etc (consult website) these services all come free with your plan and the sky sports app is a brilliant addition , these swappables are also all unlimited.
Please bear in mind that the the unlimited panther plans do not include swappables. Also orange wednesdays , free movie on thursday's from itunes are extra things the network gives.
Signal wise because the merger allows the network to use tmobile signal aswell as Orange's own masts the signal is good. 3G signal is trust worthy as you can use t-mobiles signal for 2g and 3g. 2g signal can be a little hit and miss and can drop when on the move, but over-all good.
Over-all : A good network (expensive ) but does have other features to make the network attractive , also uses tmobile signal to boost 2g/3g. Offers good extra's and very good upgrades (if you spend)
The network I use, very good signal for 2g and 3g pretty much everywhere. The deals are "average" as a new customer directly through voda. However my experiance with them (aswell as a lot of other people) is its vodafone's signal is what keep you with them. The customer service is very poor now , though I have heard they have been trying to improve it. And they are also totally inflexible (do not expect any favors at all). Despite the inflexibility they offer free extra's on high cost plans, (25mb free data per day in europe, 10free texts a day within europe) which I find very useful. Other things like vodafone passport are also very good and are one of the only networks to offer inclusive premium rate calls.
They do not offer unlimited data and cap at 1GB as the biggest bundle.
Over-all : A very good signal , good 3g. However expensive inflexible and poor customer service. If your signal comes first or you use it for business, vodafone would not let you down in that respect.
O2's 2g signal is the legend within the UK. The network is expensive and in terms of data they do not include it within a plan and make you buy a bundle. Be careful if buying from the website as you will have to add this as a extra. Good customer service is on tap.
Also offer priority moments for customers.
Again caps at 1gb in terms of data for 10pound extra per month.
Over-all : Good network , even though they are expensive. The good customer service and upgrade options give competitive over-all experience.
Over-all similar review as Orange as they use the same network.
Cheaper than Orange and deals are better (full monty plan) however they are more basic. Orange offers the wednesdays, free itunes movie , swappables etc T-Mobile is more basic but still good.
Over-all : Runs on the same network as Orange so good 2g+3g coverage. More basic and offers less but deals are cheaper and offer you more.
Cheap deals :
Virgin : piggyback network again , very cheap deals (especially if you have virgin home phone/broadband) Good for people who don't use their phone to much as the deals are cheap. Uses Orange/T-mobile so signal is good.
Over-all : Good basic network , cheap contract deal. Look here.
Tesco : Tesco network is a 3g only network , runs from O2 network.
Good deals , cheap with a good allocation of minutes + texts. In terms of rankings this is above virgin as it looks to offer higher phones at a slightly higher cost.
Over-all : Alternative to the 3 network with cheap deals.
Asda mobile : Cheeeap basically. Uses vodafone network , no good for data users as data is expensive but calls and texts come cheap. Ranked very well for customer service.
Over-all : Cheap call and text packages , though expensive for data. Good customer serivce makes this good for someone using WIFI a lot.
Talk Mobile :
This is carphone warehouse's network. Again runs using vodafone , gives good cheap deals in terms of a lot of data but less texts and minutes.
Over-all : If you dont really use your phone for calls and texts more data then this network is a good choice. Cheap deals with plenty of internet.
I hope this quick little round up of the networks help people when looking for which network to choose. Obviously always consult the signal checker on the website's. Trying to choose is tricky , but hopefully the quick points I have made will give you an idea, want features then Orange is best, Signal is vodafone , but really if you dont mind buying you own phone then no one is better than giffgaff, good signal and really really cheap.
If anyone has experiances with the networks please post away , or add to the thread
Hope this might help someone,