Algolia Pros:
* very nice UI/dashboard, stats, lots of options, flexible
* documentation is nice, 'onboarding' was not an issue
* it worked reliably most of the time
Cons:
* lock-in/proprietary. Think twice if you want to base your business on it.
* you have trust them with very sensitive customers data
* it is expensive. We reduced costs from $800/month to 40$/month by moving to self-hosted open source solution with same level/quality of customer experience.
* guys at Algolia like to rewrite client libraries and make them completely backwards incompatible. Good luck rewriting almost everything.
* support is incompetent and honestly it was useless in our case. I don't want to share details here in public as lots of people were involved in the case, but their support is disaster and for us that was major reason to migrate away. We had major issues for 2 weeks and in the end had to debug&fix problem in their client library by our developer. Long story, but that one was disaster.
In short, it wasn't extremely horrible experience overall, product is nice in general, but elasticsearch is very very good and Algolia just couldn't justify price tag, sorry.