The Editor's review of this ship is spot-on, so I won't repeat what she has written. I would like to add some thoughts based on our trip "Among the Great Whales" in February of 2013.
We had a wonderful experience. The up close interaction with the gray whales was extraordinary - and not an isolated event. Every person on the ship had a chance to pet - yes, pet - a baby whale while we were out in the Zodiacs. We saw dozens of humpbacks breaching within 50 yards of the ship and spied an enormous blue whale off the bow. Lots of sea and shore birds made for nice photo ops.
Be prepared: the cabins are tiny. If I stood with my arms outstretched, I could touch both side walls at the same time. I'm 6'4" and bumped my head a dozen times a day. Not much storage space with two people in the cabin, and ya gotta love the toilet inside the shower stall!
The food was simple, but fresh and tasty. There were always plain beef, chicken or fish choices if you did not like the evening's special meal. Wine and booze prices were very reasonable.
One note about cabin selection: there are sliding doors amidships and the cabins right next to them (like 208 and 210) have to put up with loud clangs and bangs at all hours.
We suggest that you take the trip that starts in LaPaz so that you end the cruise with that wonderful whale experience. If that had been our first day, the rest of the week would have been a letdown.