Well my system spec is broadly the same as yours, I uninstalled MBAM as it has become more of a resource hog for what it is. I gave up on SAS many years ago as it was outdated even then and tea timer could be a pain and interfere with avast.
I have had the avast free 17.x.xxxx installed on my XP Pro SP3 system from early beta's through to this 17.4.2294 release, without any major issues, a few niggles, though nothing I would uninstall it for. I too have a very minimal installation, but I'm using avast free (no avast firewall),I'm not a gamer, haven't got a web cam, so I have missed some of those major issues seen in the forums.
That said 17.4.2294 is only installed on the XP desktop system (my main system and test bed), I still have avast free 12.3.2280 installed on my win10 64bit laptop and win7 32bit netbook. I think 17.4.2294 is still work in progress and bugs are being still being squashed, but more to be done.
The problem as I see it is that not all systems are effected even on the same OS versions and this inconsistency has made fixes more difficult. I have seen one fix, resolve one problem, but cause another issue and this is a pain.
What I don't doubt, this is a big update with components/elements/functions from both Avast and AVG being integrated/modified in both programs.