I couldn't find much on this when I searched in advance, so I thought I would post about our experience for NYE 2011. We took the Stargazer Cruise from City Cruises (the cheapest one) which cost 69GBP per person. I wanted one without dancing as I was going with my 14 y/o daughter, and the only difference I could see between the Stargazer and Galaxy cruises (the next cheapest at 99GBP) was an extra 30 min of time on the river. All of the cruises sold out, so if you know you want to go, book early. I booked ours in mid Nov.
We were supposed to be at Tower Pier at 22:00 for boarding, and arrived about 21:40 or so. The loading was not very well organized, as they had several cruises which leave close together timewise but there was nothing to tell you where your boat left from. Therefore everyone was afraid they would miss their boat, so they were all pushing forward. I think they were just pushing forward for nothing though, as at 22:00 (when I think they opened the gate) the queue started moving and it was fairly simple to find where to go. The boat we were on (for the Stargazer Cruise) was mainly enclosed, but did have a small outside area at the back. When we pulled out of the pier, it was raining, but considerately it stopped just before the fireworks.
The cruise starts at Tower Pier, goes under Tower Bridge and down to the Canary Wharf area, turns around and comes back up under Tower Bridge and then stops on the other side of Westminster Bridge. It then turns around so the front of the boat is facing Westminster Bridge. They do a little commentary, but it's not really a guided cruise. If it is not raining, they retract the roof when you get under Westminster Bridge, so you do get a great view of the fireworks. The last 7-8 rows of seats will still be under the roof as it does not retract all the way. Most of the fireworks come from the London Eye side, so the right side of the boat is better to sit on. I would recommend sitting farther forward than the last 8 rows or so and right by the edge of the boat if possible as people all stand up, blocking your view if you’re sitting. However, I think if you were at the edge you could see around them. There are some that are shot out of the clock tower at the Houses of Parliament, but (this year anyway) they were only at the very beginning.
The cruise ends at Westminster Pier, so you do have to fight your way through the crowds when you get off. It would be nice if it went back to Tower Pier as that way you could avoid the crowds. I’m not sure why they don’t do it that way. The cruise itself was very family friendly (although it was mostly adults). They give out a bag with a water bottle, mini champagne bottle, bagel with salmon, and crisps. For the kids they have a bag with coke instead of champagne, and I don’t think DD got a bagel, but I’m not sure what she got instead.
Getting off was ok until you get up the steps to Westminster Bridge. At that time (about 0030, I think), the police had barricades up so the people on Westminster Bridge could not leave. I heard someone say they don’t open it up for an hour after the fireworks, but I don’t know that for a fact. For some reason, there were a bunch of people pushing to go towards the bridge, but I don’t know why they were going that way. I just grabbed DD’s hand and sort of bulldozed our way through the crowd, keeping her behind me. I would not recommend this part for small children or people who are claustrophobic. However, it didn’t stay that way for very long, and before we had gotten all the way past Parliament it started to open up a little and we could walk normally.
We ended up walking to Green Park because I knew where it was and that it wasn’t a bad walk since I’d done it before. The Picadilly line was actually fairly uncrowded, and even had extra seats. It looked like the platform going the other way (towards Heathrow and Uxbridge) was much more crowded than ours going towards Cockfosters. Overall, I found it fairly manageable, although I was glad there were only 2 of us to keep together, and I’m not sure I would have wanted to be packed in with all those people for all those hours. I was glad I had paid for the cruise. Also, there are toilets on the boat which were not the nicest ever, but not the worse either, and there are few enough people that there was never a queue that I saw.
Overall, people were fairly well behaved (London in general, not the cruise, there were no problems on the cruise with overly intoxicated people). We did see one young man on the ground behind a police car. DD says he was in handcuffs, but I didn’t see that. There were also a couple of drunks on the tube, one yelling that no one better stand in front of him, although his language was not that polite. There was also one that got on at Holborn who could barely stand up. He was not being threatening, though. I was more concerned that he might fall over on us. Fortunately, we were getting off at the next stop. There were also some groups we passed when walking to the station who appeared fairly intoxicated, but they were not interfering with anyone else or being threatening.
The only places I could see that might have had a better view than we did would be on the London Eye side of Westminster Bridge or Jubilee Bridge (Westminster being closer and probably better) or on the Victoria Embankment if you can get towards the edge of the Thames between those two bridges. I think then you would have a better view of the ground level fireworks as our view was partially blocked by Westminster Bridge. I would suspect that those viewing areas would fill up pretty early and would be very crowded, so for that I think the cruise is better.