I’ve had both and I prefer disc for every type of riding. It’s the new standard so people are going to have to get over it. I know there’s a little bit of a weight penalty, but I’m .5-1 mph faster at all times on my new disc bike compared to my rim brake bike. I don’t feel like anyone will notice a drop in speed due to disc, if they do there’s probably more factors involved than just the disc brakes.
From talking to people on rides and listening to the debates on forums, it seems that most of the people that are against disc brake bikes are those that spent a lot of money on their bikes and they don’t want to hear/think that they have an inferior bike. Yes rim brakes have worked for years and will continue to work for years, but there is in my opinion a better option.