Any experience building native mobile MVPs based on web apps?

Do you have experience building a native mobile app based on a web app? Specifically, I'm looking into Bubble.is for basic MVP development (web app) and into Dropsource/Thunkable + GoNative.io for mobile development.

Among other things, I wonder about the quality of the code one can realistically expect to get from these apps and whether I'll be able to further build on top of this code in Xcode if/as the app grows. I'd really like to hear from someone who has a first-hand experience! Thank you!