I did see a lot of the same vehicles used for the desert safari doing private tours during the day. At that cost I think it would be a good way to go and fun to all be together. The HO HO buses get you around but it is hot.
Burj - well I would not compare it to the hotels you mention like the Belagio, Venetian etc. To me these fall in the large, classy, beautifully decorated hotels. These hotels focus on the stunning lobby and public spaces with nice but not outrageous rooms.
To me the Burj goes the other way. Incredible rooms (which we did not get to see) and the lobby is not really large or in my opinion that special. I would guess that it would be considered very garish in decor for most Americans. For me it was more fantastic on the outside than the inside. I think the outside design is amazing. Marcie's pictures of their room during their stay really made me want to stay there just once. Not to be on this last trip.
That said I think to make a decision to "not go in" on your only trip to Dubai you may regret. Inside I personally found it a little disappointing. I imagine if we had stayed in a room I would have liked it much more because the rooms are supposed to be really stunning.
I did the tea, glad that I did that, seven courses just a little over $100 - a meal in fact. The problem was it took over 2 hours so ate up a lot of our day. I would suggest it once but I would not do it again.