Hello there! Might as well join this thread as I'm a Linux user as well.
I have Arch running on all computers that I use around my house. My sister complains, but I think she secretly likes it :)
She would complain of it being "slow" when I had the desktop she uses running Ubuntu (even though it was slower when running XP), but then again it's an old Athlon 64 machine. She can't complain anymore with it running Arch though. I have her set up with LXDE along with Compton and Docky. Considering that it's a graphical environment and there's compositing involved, it runs very smoothly and snappily. I had it using LXDM, but that's kind of ugly and I didn't want her complaining so I switched it over to LightDM, and while it's slower, it does look better.
I also run Arch on my laptop which I use for web browsing, schoolwork, music listening (very close to ordering my first audiophile headphones), etc.
I'm pretty content with the default Cinnamon setup, but I've been experiencing some bugs, so I'm not sure I'll stick with it. I might duplicate what I have set up for my sister, but I'm also interested in i3 as many, many people on the Arch forum seem to use it.
It's a pretty old machine (I think from about 2006), but it performs very nicely for its age.
I have upgraded the ram from 1 gig to 4 gigs, upgraded the HDD to an SSD, and also upgraded from a Core Duo to a Core 2 Duo from my mom's old laptop which finally died (motherboard problem, I think). She was using a new laptop with an i7 long before this happened though. My graphics chipset is atrocious though, it's an Intel GMA 450.
I love Arch. It's flexible, customizable, but also super easy to use. I doubt I'll ever go back to a simpler distro. Once I get a new laptop (not likely for a couple more years), I would like to experiment with Linux from Scratch on my current one.
I also recently did some work with Raspberry Pis for my dad. I have to confess, though, that I wasn't a fantastic help, as I didn't have any experience in what he wanted to do with them. He's involved in the video streaming business, but I've never done anything with the likes of Wowza or ffmpeg before. Oh well.