The choice of GUIDE vs App Designer is easy:
If you do not have much graphics experience, and your needs are not complicated, and you are using an older release like you are (R2017a), then you should use GUIDE for the first while. GUIDE is a mess to do detailed GUI in, but as a starting point, it is useful .
If your needs are more complicated (such as needing to be able to reflow sections as the user resizes), and you are using an older release like you are, then you should write the code yourself.
If you are were using R2021a or later, then GUIDE would not be an option, and in that case you would have to consider whether the execution slowness and editor crawling and the limitations of using App Designer are worth putting up with for the nice parts it does have.
App Designer in your version (R2017b) was not very developed and did not yet have some important performance improvements; the only reason to use it back then is that it made some things easier, and the fact that GUIDE was going away was already known back then.
In current versions (R2021a), the reports I read imply that App Designer is unusable for larger projects at this time: by 3000 lines, editor response is reportedly often in the minutes range.
"The choice of GUIDE vs App Designer is easy, you should definitely use App Designer"
Only if that is followed by "... for your toy apps where your development is more of a learning experience to get you ready for future use, rather than if you need to build something that people will actually use."
... If it sounds like I am contradicting @Dave B in my answer, it is because I am contradicting him. App Designer is Not Ready For Prime Time, and is unlikely to be for at least two years.
App Designer is currently, at its best, like going back to dial-up.... to another country.