It’s me desperately searching for some reasons why to prefer one over the other, which is in my experience Denali over Everest, as my Stackwise-Virtual Stack crashed heavily with Everest and while fixing it, the IOS was wrong provisioned by the master leaving both in ROMMON, so i had a bad start with Everest and am not recommending it to our customers. But some raise their eyebrowns about this explaination, nevertheless they are on my side.
Whats the REAL reason to go with any of those?
3.6.X is out as it does not support stackwise-virtual? and if you have stacks, you want to stay consistent in your infrastructure, right?
For those that may not be familiar with these names, each one refers to a version of the ASR-1001-X IOS. Specifically, Denali 16.3.5 (MD), Everest 16.6.2(ED), and Fuji 16.7.1 (ED).
When choosing IOS versions, there are several things you should keep in mind. The first is that older versions are generally more stable as there is enough time for bugs to be found and fixed. Newer versions generally have a richer or at least more updated feature set. Which you use really depends on personal experience, as in your case, but also stability and desired feature set. A balance of these will probably get you the best result.