I'm not sure if things have changed in the last 2.5 months, but that's not really a fair comparison on 22 April. I'm looking at a Compute Stick on Amazon right now for $77.80. That includes a power supply, 8gb built in storage, and a case. Add $10 for a USB ethernet adapter. Most RaspberryPi "Starter Kits" are about the same price range, or at least in that ballpark.
I don't know the cpu cycles comparison between the ARM in the RPi3 and the Atom in the Compute Stick. The RPi3 might be a better value strictly from a computing cycles perspective. Which is shocking since the RPi has not been a very good value in that particular category in the past. That was never an objective of the RPi, which is exactly what makes it attractive. The Intel does have a distinct advantage with a broader base of available distros and compiled binaries available for the CPU.
The big advantage that I see to the Intel Compute Stick however, is the eMMC built-in storage. There are so many flavors of MicroSD cards on the market, choosing one for the RPi3 that can handle the read/write of a modern OS, can add some stress to a purchase. I hope the smart people at Intel vetted their eMMC and it's engineered to handle read/writes of a modern OS. 8gb is not very much, but it's probably sufficient for most Asterisk installs that might go on this stick. You can add file storage with a MicroSD. If you're only storing some files on that MicroSD, you don't need to worry about getting one appropriate for OS read/writes. So the MicroSD purchase is more commodity.
I love my RPi's. I have quite a few of them. I'd really like to see how the Intel Compute Stick compares running Asterisk. Running down the list feature by feature, I think the RPi3 is still a better value. But it's rather close for me. It's not a 1:4 ratio.