I do not have any experience with HS so cannot comment. For me HE + NR does the trick otherwise if I HAD to maybe Home Assistant + NR but I would be very unhappy about it.
FWIW, I have zigbee motion/contact sensors on one Hubitat triggering a z-wave+ switch on another via Node-RED. The lights reproducibly come on in under 200 ms. This is very similar to what I get using either Motion Lighting or Rule Machine. Caseta dimmers are fractionally faster (about 160 ms).
My Motion Lighting automations are still happily executing in the 100ms-175ms range. Zigbee Iris v2 motion sensors and Lutron Caseta dimmers/switches. Been running great for years now. No corrupted databases. No scheduled reboots. Knock on wood, it's been running smoothly for quite some time.
I don’t know how it compares to homeseer since I’ve never used that platform, but Hubitat has a few different apps that can be used to write automations (aka rules).
Rule Machine is by far the most complex, flexible, powerful etc. And yes that makes it the least intuitive option even within the Hubitat platform. But other apps like Basic Rules, Notifier or Hubitat Safety Manager are pretty straightforward to configure.
Think you will find that while there are always exceptions the problems you are describing are not occurring, or are not occurring at a rate that is statistically significant. (Of course if you are that 1 in a million occurance you’re not going to be happy. )
Because even with your last hub, your experience didn't mirror mine or that of several others. Since each situation is apparently distinct, your past experience would suggest it is most productive for you to determine functionality for yourself, instead of relying on the experiences of others.
About all we can tell you is that many of us didn't have - never had - the issues you describe. The C7 hasn't changed all that much over the past year, in my view. Firmware updates have occurred, but it's not as if any of us seem to be able to say, "Oh, yeah, that was fixed in version x.x". So, we welcome you, but we can't point to anything specific to give you increased confidence for your particular situation.
It's rather like a group of friends who all go to a restaurant and order a bunch of different dishes that get passed around, with everyone trying a little of everything. The next day, one person becomes ill with something that resembles food poisoning (but only one). It's very hard to convince that one person that something wasn't right with the food, because of their experience. But the others just had a great meal. So, if you're that one person, there comes a point where you just have to decide whether to go back to that restaurant, or not. Whatever you decide, we wish you well.