I've gone from native Windows 7 -> 8 -> 8.1 on one machine via upgrades.
Only issue I had was with quirky drivers that needed to be massaged when I went to 8 and removed entirely when I went to 8.1 Believe it was some Conexant audio driver? The issue had a solution once the respective OSes had been in the wild a couple of weeks.
I liked 8 fine but I entirely skipped 7. I've recently gotten another machine with 7 on it and I understand a lot of the bitching.