But if you just want to look at pictures of asian sirens (or fashion models, or typography, or flowers), it’s great. Every time you click on an image you are offered a choice of similar images. Similar images are apparently identified based on tags, so tagging is important.
This set of images is basically what you get by searching for photos related to the tags asian, girl and breasts. Unfortunately, you can’t just directly search for multiple terms, so the only way to see these sets of related photos is to use related photos as your query. That drawback is typical of the amateur feel to this site. This is most definitely not Google, but they do have tens of thousands of users, and they seem to be very sincere about making it all work better.
In conclusion, WeHeartIt is a lot less useful than vi.sualize.us, but it does have a lot more photos of asian sirens to look at.