I tend to browse FP a lot on my Laptop mostly. Desktop it's only like 3% of the time and via phone is when I'm aware or not at home, even then that's 8% of the time.
I mainly access the site using my desktop PC. I can't remember what my password is otherwise I'd check the forums more on my phone. :V I need to re-sync Firefox again since it's not storing my passwords on the mobile version...
I have always accessed the Forum Promotion community using my mobile phone. The site loading speed is good and that is something that I pretty much like about this site. The user interface is also pretty okay and you can't say you are not getting it right once you setup a forum like this.
Desktop computer is how I do most of my foruming stuff. If I need to check something while I'm away from my computer for whatever reason, I'll use my phone, or if I'm at home and simply don't feel like going to my computer, I'll use my tablet.
I primarily visit Forum Promotion on my desktop. There are a few times where I will visit on mobile, if I feel I need to check up on something while away from my desktop.