Just realized I could've answered your question much more simply. Samsung with their Exynos chips are doing all the things Qualcomm's Snapdragon chips are doing as far as what Qualcomm is talking about, meaning the Exynos has CPU, GPU, ISP, DSP, etc just like the Snapdragon does. Pretty sure it even has an integrated modem which is the main thing that Snapdragon chips offered that others didn't.
Trying to compare them across the board is quite difficult, and there's a lot of issues trying to do that. Ultimately it is pointless as it depends on the end devices using them.
There is a good situation, and I have a hunch this is what you are actually wanting to know is, which is better the Galaxy S8 (or maybe S7?) version with the Exynos or the Snapdragon chip better. And it will depend. I think on the S7 the Exynos was considered a bit better (think it had fairly similar performance but tended to offer a bit better battery life; also think it was considered to have better sounding audio, but for the most part the differences weren't big, and were dwarfed probably by manufacturing variability). I don't know if one received better/quicker software support. Others can probably answer that better.
I don't know if that's really been compare much or in depth yet on the S8s though.
You should be fine either way, as they're both decent and you'll likely not notice the difference in most uses, so go for the one that is most compatible with your network, and then whichever one you get a better deal on. They tend to be offered in specific markets (which means if you buy one for a different market you won't get the warranty).
Qualcomm heterogeneous computing refers to cpu, dsp, gpu, isp, sensor core, display egnige, e.t.c.
That's just Qualcomm marketing spin and is not what heterogeneous compute actually is in how the industry is going about it. Plus half that equation, the stuff like ISPs/DSPs/etc already had to work cooperatively with the CPU/GPU so there was no change other than over time they added more of those to the SoC vs them being separate chips (has advantages and disadvantages, but in mobile the advantages largely outweigh the disadvantages). Most companies making SoCs had already integrated that stuff though.
Qualcomm is trying to make it seem like other companies are just doing big.LITTLE stuff for heterogeneous compute, which isn't really what that is either, and isn't the reality for the competitors who are doing pretty much almost all the same stuff Qualcomm is. The main notable exception being the modem, although Samsung is integrating that I believe in their Exynos chips.
Really though all of that is getting into semantics and technicalities and doesn't really answer your question, sorry for the confusion.