My wife and I went with Linblad/NG in late January - early February, 2011. We were very pleased with the level of service, the professionalism, and the quality of the overall experience. We have several friends who went with Linblad and also gave them high marks. In fact, one set of our closest friends are in Peru with Linblad now, having done the Galapagos cruise last week.
They are expensive, but well worth it in my view.
If you want to see what it is like, our pictures from that trip are here.
We went in 2003...... I didn't have near the quality gear I have now. The 70-200 (and maybe a 1.4 tele) on DX was great! Your new lens would be ideal. I highly recommend it! We did one week at Machu Picchu and 1 week in the Galapagos! Very easy to do both on one trip.