Democrats or Republicans will win most races.
To the extent Democrats win, health insurance may be less expensive in the long run.
To the extent Republicans win, IRAs and 401ks and "wealth" are less likely to be taxed in the future.
Partisans on both sides will argue strenuously that their party is best for the middle class, while spending most of their time and efforts on their own re-election.
In the end, what you do personally will matter much more to your own situation than which party wins more races.