I also get those compliments and I also just use shampoo and conditioner (once or twice a week). When I travel and use hotel shampoo/conditioner my hair usually feels noticably worse after (sometimes the hotel stuff is actually nice though).

I think a lot of it is genetics, and not coloring or bleaching or anything also helps a lot. But conditioner is great and not a scam (and I don't let the male targeted 2 in 1 soap/shampoo stuff anywhere near my hair anymore, that was noticably worse as well)