Los Llanos or Orinoco Delta or Gran Sabana ?

I am preparing a 15 days trip in Venezuela this summer, and got in contact with several travel agencies there -

I'd like to do some of the following:
- for sure: 3 days 2 nights tour to Angel Falls
- for sure: 3 or 4 days in Los Roques (just getting the flight and reserving a posada)
- 4 days 3 nights tour to Gran Sabana
- 4 days 3 nights tour to Los Llanos (with maybe 1 additional day in Merida, or maybe directly from Barinas)
- 3 days 2 nights tour to Orinoco Delta

Now, some agencies are telling me that Los Llanos and Orinoco Delta are quite "similar", and LL would be better as there many more chances to see animals ... other are saying that Angel Falls and Gran Sabana are "similar", and that if I see Angel Falls then GS is not a must ....
As I cannot see them all, can someone explain/suggest if the above is true, and what would be the best choice between
- Angel Falls Gran Sabana + Los Llanos Los Roques
- or Angel Falls Orinoco Delta + Los Llanos Los Roques
- or Angel Falls Gran Sabana + Orinoco Delta Los Roques

Many thanks in advance !!

how was los roques, i'm going there in November and am looking to stay somewhere nice and stay busy for 3-4 days. Do you recommend staying at posada or yacht? Any deals/excursions that you recommend?

Riccardo40, I'm kind of in the same dilemma. What di dyou decide to do?

I just came from Venezuela, where I had 15 days: we did Canaima/Angel Fall (Tiuna Tous), Orinoco (Tiuna Tours), Merida, Los Llanos (Tony Martin tours), and some Caracas and beach. We did all that we planned with no delays - now is a good time to travel there as there are not too many tourists, and you can quite easily buy night-bus tickets. If I had to delete something from our itinerary it would be Orinoco - if someone has a dilema what to choose: Orinoco or Los Llanos, I say Los Llanos.
As I already posted in some other location - my choice for a Los Llanos tour is with Tony Martin. I was amased by the trip and by Tony himself. He is biologist, studied ornitology at Boston University, and he treats animals with great love and respect. He is the most experienced (and famous) guide there, and his trips include boat safari, jeep safaris, night safari, horse safari, pirania fishing etc. Everything that was promised was fulfilled. Toni owns now a new camp in Los Llanos, with a swiming pool!!! yes!, and the time we had there was the best from all in Venezuela. I can strongly recommend him: extremexpeditions@hotmail.com. The office of Extreme is just a few doors left from Guamanchi. Check this out: http://www.hosteltrail.com/extremexpeditions/