I've done upgrade installs from 7022 to 7048 and 7057 with very little to zero problems actually, more or less to test how well upgrade installs are working in the latter builds and so far I haven't seen any deal breakers that would force me to do a clean install to fix things. I'm going to do a clean to 7068 tho, just because I'm in this big "cleaning" mode and getting rid of stuff I've been storing for a couple years now and not using anymore. I probably have 180G's of program installers I haven't run since late XP, early Vista days so it's gotta go.
Concerning ESS tho, I was on the ESS beta team and had direct contact to Eset engineers to talk about issues. The ESS firewall when first released was known to be about a 3rd tier firewall at best but Eset needed to release ESS so they ran with what they had but had a very extensive list of improvements to work on. The next release made some of them but it's still not a quality firewall yet, and that's why I simply can't use it or recommend it. I LOVE Nod32 AV but I use Comodo firewall as it's much more capable than Eset's is ATM.
Quality firewalls take time as they are no longer simply an Enterprise strength packet filter, todays threats have evolved way beyond that. While my habits these days keep me pretty insulated from emerging threats, my past security work reminds me just how important proper security is for the average user. HIPS protection for all but the most security aware users is almost a MUST now and ESS firewall just hasn't gotten to that level yet.