We did our research, narrowed it down to 2 companies before we settled for Realtyna. Started working with the Realtyna team the end of October, our RETS based solution website finally launched the first of January along with their IOS and Android App solutions. I can't say enough about the service I received during the 3 months of integration and setup. There were some issues, but nothing that could not be overcome by the support team. We chose to go with hosting with Realtyna, that way we knew everything would work as expected. Lika trained us on the ins and outs of the plugin, and she did a fantastic job. She also acted as an advocate during the times we had issues. She communicated well and got things done for us. Although they say they are based in the USA, the hours they worked seemed to fall inside a European time-clock.
If we had it to do over again I would still go with Realtyna.