We will definitely be checking this out. Our experience with another vendor and ES has not been great. From having the whole cluster come down when we're doing batch inserts for initial loads to having 10s timeouts on random queries during low activity windows with the vendor saying "dunno, everything looks good here" (when we measured that this 10s were spent waiting for ES).
If you're looking for a search backend without having to worry about managing infrastructure, you should check out Azure Search. I'm a dev on the product. If you're interested in trying it out let me know. You can ping me at my username @microsoft.com if you have questions or need pointers.
