I am currently writing a few different apps some of which I wish put in the App store. However, I would like some advice. I am a software engineer but i'm not strong with UI. I have written a few apps but I have always been disappointed with the UI. My question is, do you think people will be turned off from using my app if the UI is really ugly? Is it worth my time to hold off on deploying the app to get the UI more fine tuned? Where can I learn to design higher quality apps?
Depends... functionality is very important. I bought an app that has the most horrible UI design, but the functionality is outstanding. But also you have to understand that beauty is in the eye of the beholder. Some people will like the UI of your app, and others won't.
Don't hold off deploying your app, put it in the App Store then continue to refine the app with updates. Explain in your description what your app does exactly, and make sure that your app does that. Even if your app works perfectly, there's always someone that will give you a 1 star review because they are stupid or did not like to read instructions and expect something different. Don't dismay if this occurs, talk to the Apple review team and ask them to review your app, and if your app perform with flying colors they will remove the 1 star review.
There's always hope! I know it feel awful when they give you an unjust review, it's your creation after all, but before you do the final touches for the UI, please make sure there's no bugs in it. Test, test, test, test that app... jajaja Because someone in this planet when they buy your app will do something that you did not test against and your app will crash... being there jajaja Now I can laugh, at that moment I was upset. They were using it wrong! jajaja That's how we learn, by mistakes.
You have to learn how to make buttons, backgrounds and use the correct fonts with the correct colors. That in it self is an art. It takes time to learn, be patient and put your ego under the sole of your shoes... it helps when you ask somebody for their opinion about your app. Good luck!!!