I have recently converted everything I own over to Arch (save my phone, but huge shoutout to XDA developers for pwning the Verizon Galaxy Note 2).
I recently bought Aspire One 725-0687 (Dual core AMD C70, 2GB DDR3, 320GB HD, Broadcom 4313 (sigh) wireless).
I knew it would be slow as dirt, but I thought I could gut Windows 8 from it and replace it with Arch and have a nice cheap netbook for trips.
Out of the box Arch (and every other distro I tried) sucks. Brightness control doesn't work, wireless drivers were flaky at best with terrible reception, sound would always mute itself after locks, sometimes it wouldn't wake from suspends correctly, and the hard drive would have massive lag spikes. The one item that honked me off the most was the brightness since it hammers the battery and defeats the purpose of having a netbook with good battery life.
I was on the verge of throwing it in the trash (aka my closet). Then I decided, as a Hail Mary of sorts, to look for a kernel closer to the bleeding edge, since 3.6.11 wasn't getting it done.
Follow the instructions and install the ck-bobcat kernel. You will want to install the kernel, headers and broadcom driver from the repo. If you do a pacman -S ck-bobcat, as of right now they are options 1 2 3.
Also, follow the wiki and enable the alternate HD scheduler, it helps.
After doing this everything on the laptop will work as expected including brightness controls. Over all the laptop seems faster.
Known Issues: The HD activity light is constantly on, I image this has to do with the scheduler. The wifi is much more stable and better range, but it still sucks compared to normal wifi cards.
I noticed a lot of threads regarding this series of laptops on many linux forums with no solutions so I hope this helps someone.