I booked the Luxury Day Tour to Halong Bay via Awesome Travel. They were very responsive in my email enquiries and ensured they were able to pick me up from a hotel quite far outside of the Old Quarter, so it was quite a hassle free arrangement. The van was very comfy and the 3-hour ride each way didn't feel too bad...although be prepared the road can be quite bumpy (but not the travel agent's fault)...but thanks to the comfy van made it a lot better.
We had a good tour guide who spoke very good English. He was able to give quite a lot of interesting info about Hanoi and Halong Bay. The amount of info was not too excessive and not too little, so just about right. The only comment I would have is that he wasn't able to accompany us into the Cave visit (due to an incident that a member of the tour was missing so he had to find the missing member) so he wasn't able to point out to us those interesting-shaped rocks! But no matter, we listened to other tour guide's explanation so it was alright.
The only thing I would comment was that the seafood lunch was quite basic, although there were fish, squid and prawn but the quantity per person was a bit too little. I was at a table with 4 guys and we had to share 1 small plate of rice, 1 small fish, a small plate of vegetables, squid and 1 small prawn per person. As this was a luxury tour and the cost was double the normal tour, I had expected the lunch to be at least enough to fill my stomach. Other than this, we were quite happy with the rest. I would recommend Awesome Travel to other visits!