In your opinion which one is better and why?
That would depend on a number of factors....
what are you doing with the laptop? Does the laptop feature a dedicated gpu or are you using the integrated gpu? What are the costs of the two options?
A few points on the two are: The i5 1035G1 is based on Intels latest 10nm SunnyCover core so the cpu side is much stronger than on the 3500u (which is a first gen Ryzen based part) so for cpu heavy tasks the i5 is going to be faster. It should also use a bit less power being a 10nm cpu vs the 12nm for the 3500u.
Graphics wise, the Vega gpu in the 3500u is quite a lot faster than the gpu on the i5 so if gaming on the integrated graphics the Ryzen cpu is a better choice.
If the machine...