Kelley Blue Book has posted up a detailed comparison between Genesis new sports sedan and the established C-Class. They found in terms of value for your money that the G70 is a better buy, with its great list of standard kit and an incredible warranty package. It is however at a disadvantage with brand recognition and a prominent dealer network. Cant hyperlink yet. kbb.com/car-news/all-the-latest/genesis-g70-vs-mercedes-benz-c-class-comparison/2100006303
The G70 has been developed for those that are budget conscious and looking for something that's less expensive to maintain. Owning a C-Class or CLA out of warranty is going to put a hole in your pocket.
Even though Genesis does have the advantage, where they don't is with Lexus that sells far more models and shares parts among a wider range.
What this means for the long term are cheaper and easier to access parts.
While there will be some new owners coming over from competing brands, many will probably be current or previous Hyundai owners. Badge bias comes into play with any new vehicle launch, and there will always be a risk with buying in early.