I have been on the London Eye.
When I went on it, it cost about £10 and it took around 30 or so minutes to go around it.

It is a huge round wheel with pods what people go into to view London from the air, each pod is quite big and it holds about 15 people or so, and you can see for miles from the pods and you can freely walk around it inside, you are not in a seat, but there is a large bench inside to sit on if need to, although alot of people are in the pod with you, it is still roomy enough to view from, it is not crowded as you would imagine when you first see it.

There is a queing system, although if you go at the right time it is not too long and the queue soon goes because alot of people go into one pod at a time, and so the queue reducing very quickly.

It can be pre booked and so then you can go to a different pay desk, although I did not do this I think you have to book a time to arrive there, which helps them and yourself, It is a good way to beat the queues and I myself have done that with alot of London attractions as to save waiting around and getting tired, and it is handy if you have children too.

Children would find this exellent as it is not as frightening as you would think, it is not like a big wheel at the fair, it is totally different and well worth price for London, although 30 minutes does not seem long enough it actually does not feel that short, it tends to feel alot longer than that.

It is well organised too and there is no pushing inside the pods.

Well worth a visit if you live or are visiting London