A night tour is the best way to see wildlife in the Monteverde area. We have taken this tour twice now and found it to be excellent. The area covered is small, but there are a lot of animals roaming and resting there. We saw a sloth that was actually moving (relatively) rapidly from tree to tree, a kinkajou, two gray foxes, a coati, some snakes, many birds, and, amazingly, a margay! We were extremely blessed to see a margay (see photo). The guide told us that they see any wild cat only about twice a year and when they do see a wild cat, they usually just get a glimpse as it runs off. This margay sat in a tree and posed for us for at least 10 minutes before running off. It is a threatened animal and very rare. It was a beautiful animal!
Our guide, Michael, was young but very knowledgeable. One caveat is that he moved fast and my wife had trouble keeping up with him on the rough trails.
I highly recommend this night tour. You are unlikely to see the margay, but you will see lots of critters.