I have just finished IG Turris Omnia migration.
It did require more clicks in foris to get it running and then in reforis (that I had to fix via Can not use Reforis on TOS 5+ - ControllerMissing - #17 by encacz)
HDD with Omnia still works fine.
PPPoE - no issues.
VLANs migrated, but with one issue. Interfaces that were visible in luci did actually not work and had to be SET by set
set network."VLAN_NAME".ifname='lan"0 or 1,2,3,4,5"."VLANID"'
e.g. set network.management.ifname='lan0.10'
So these were three major issues.
One small issue is that automatic updates did not do all the work and had to be triggered more times in order for the process to do someting.
I have also received no notifications during the process (I had them enabled)
After manual update clicking on manualy fixed reforis I got first notification about restart - and that was all.
EDIT: Third issue - collectd is still not working. Same problems as in v15.05 of openwrt fork. I have been able to make it work in the past, but updater damaged changes and made it broken again.
So I hope this package will get fixed soon. It is time