[whirlygigg]

Anyone have experience with this GPS unit? It's available on Amazon:

http://www.amazon.com/Jrelecs%C2%AE-Openpilot-Revolution-Filght-Controller/dp/B0179GAU8O/ref=sr_1_1?ie=UTF8&qid=1451398780&sr=8-1&keywords=openpilot+gps

And also this one:
http://www.amazon.com/Andoer-Precision-Multirotor-Quadcopter-Controller/dp/B00N3TE312/ref=pd_sim_21_3?ie=UTF8&dpID=411VDcFx8mL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=0D8AKV8F4E5FTCNRHG9T

What is the advantage of a built-in compass?

For $16 bucks, it seems low risk. Any opinions or advice appreciated.

[TheOtherCliff]

I recall that first one looks like the one that does not save settings and so it only works with Revo class FC (not CC3D).  Also does not have a mag that is good for doing GPS guided flight on Revo etc.

The second one looks OK, and has an external mag that you can use with next release (soldering required for connectors), but it is only a Neo6.  I know you can get better and cheaper than that, at least on eBay.