We tried this app for a week in trial and the support from Roman was typically within 24 hour reply or sooner. Which is good. This options app is hosted on a server by the app provider and therefore all options are under the control of that server and should it fail so too would your options. We found that compared to our current options the load time on desktop was not too bad but found on mobile devices (70% of shoppers are on mobile) the lag time was far greater. I think the options display far better in the cart than competitors options and should we have had a localized solution that provided our options we would surely have gone for that. Until such time as we find a better solution, we'll stick with our current options application, unfortunately.
I'm really sorry to hear you disliked the app due to the fact it is hosted on our dedicated server. Shopify is a cloud platform and all apps dealing with the Shopify API should be hosted on the app owner's server. App can't run without a server. We also have a FAQ section explaining how to load the app faster. You just need to add one line to your theme's code. That's a few minutes task. The app doesn't modify the theme itself like some other apps do. So it can be safely installed and uninstalled. Also, it's a shame to get such a resolution after hours of my help with customizing CSS and JS for your 2 themes. Every your request was replied timely with free customizations made specially for you. There was no word about the mobile speed, unfortunately. We would have fixed it easily. Hope you will find a solution that better fits your needs!