The most stable Cubase I've had in years. I'm quite happy.
How stable is it? Really stable when you consider what it has to contend with.
Stable doesn't have to (and can never) mean "perfect." No DAW or any software is 100% free of bugs even when it controls 100% of the code. Cubase has to host all our beloved 3rd party plugins, from all parts of the globe, from all manner of software developers with their own level of expertise, skill and ways of coding. With multiple formats of those plugins, no less. In dual platform, no less. We won't even mention audio interfaces, drivers, or the OS and its layers, itself.
No technology service guarantees 100% up-time. Not even Tier 1 technology providers that get to enjoy multiple levels of redundancy, that a single computer does not.
Even the hardware is not 100% crash-free at a quantum physics level. Naturally occurring radiation and cosmic rays will statistically crash a computer with non error-correcting ram as much as once per month, per gigabyte (if left on).
For our modern computers, which many of us leave on for days at a time, with our non-server-grade, non-error-correcting memory (just about all of us here), this would translate into 32 times a month (for a system with 32 gigabytes), or about once a day, that we could statistically expect the computer to potentially crash, regardless of software ("potentially," because not all ram errors would result in a crash, but many do).
I've even had hardware sequencers lockup and require a power cycle.
A DAW would certainly be in a top ten list of the most sophisticated desktop software products created by humans. I put it at the top of that list, due to how many 3rd party programs it hosts and the real-time, latency-oriented nature of it.
So, yes, Cubase is pretty darn rock solid from where I sit. I'm in awe at how many plugins it juggles and how little it crashes.
iTunes crashes more than Cubase for me. Which gets funnier the more you think about it.