aaabaaab
https://odroidinc.com/blogs/news/odroid-n1-the-next-odroid shows the benchmark results Odroid published and they claim "The performance was not significantly different from XU4".

Your MIPS ratings for the XU4 assume you can run the big cores at 2.0GHz all the time, which I have not found to be true, because it will overheat and throttle itself. Try running your numbers again at 1.9GHz or 1.8GHz for the big cores then see how the MIPS compare.

You can use the CPU-Z app to see what speed your XU4 cores are running at in real time.

I believe the N1 chip will cool better because of the metal package and it has fewer cores generating heat, so it may be able to run all the cores at their top speeds all the time.

Can't a usb fan be blown on the odroid? i bought a usb artic cooler fan for $8 which is fairly quiet and keeps my USB ASIC cool enough to overclock.

I have mine in a box that is effectively a wind tunnel, with a 120mm fan pushing air over the odroids, and a 120mm fan pulling the "warm" air out. I also have oversized heatsinks attached with thermal paste, and a noctua 40mm 5v fan on top of the heatsink. Often, the 40mm fan is not even running, because the thermals hover around 60C and the odroid does not feel the need to run it. Short of dropping it into mineral oil, it is as cool as it is going to get for me.

Rather than pay a premium on best model, perhaps second generation processor will provide better value and I can pick up a cluster.

The Fire3 looks interesting and the price is low.
My concern would be that 1GB of memory isn't very much for 8 cores. You may not be able to run all the cores at once without running out of memory.
The heat sink won't be able to keep it cool running all cores at 100% without adding a fan or going with a larger heat sink.