I just updated a few details in my FAQ on this subject, not really all the differences but most of the similarities. If you click on my signature under this post you can read a little bit about it.
I personally use the AP for the tuning software but some people will tune their car once and be fine for months,years so the ap then becomes a paperweight unless you take advantage of the guages and logger to monitor.
Opensource requires a laptop, setting up the software and can be frustrating at times but very rewarding once you get it working.
There are benifits and drawbacks to either setup when it comes to AP vs OS, do your research and figure out what works best for you.
Stage 1,2 & 3 E-Tuning Click Here For Details
Last edited by cryo; 09-23-2012 at 08:20 PM..