Sync Local Postgres Server to Cloud?

Hi everyone, we have a POS app that runs on Postgres on the Mac on a typical client-server platform. We really would like to add cloud based support. We are not interested in redesigning the application to run exclusively off the cloud (atleast not yet). I had the idea of continuously syncing directly to a cloud server but keeping a local Postgres DB as the primary server. This gives the user the ability to do things like run reports off the data in the cloud at an enterprise level, as well as keep an ongoing backup of the server that could easily be restored while not having to deal with headaches of exclusively cloud-based products.

I have read up on several ways of doing this (log shipping, slony-I, etc) but there seems to be so many ways to do this and the pros and cons of each are not apparent to me. Im wondering if anyone could provide some insight into the simplest way to do this? We really need to maintain a good balance of reliability and speed, and its got to be a solution that could be easily replicated for each user of our software who opts for this service.

Thanks in advance.

-- Mark Adler
Prosperity POS