For a short while, I recently played Hardcore Mode in BF4. While I had fun playing it, I've ultimately decided to return to playing Regular Mode.
Why? Because I find that Regular Mode has a faster, more fun gameplay style for me. Hardcore Mode just attracted too many campers/snipers who were content to camp and snipe at other gamers for the entire game round.
While doing so was fun for them, I just didn't find that gameplay style as enjoyable. So it's back to Regular Mode for me.