tsiwt
Already the fact that they haven't release 19 yet is a big turn off, when blender and c4d are pumping out releases every few months.
You have free access to daily builds with bug fixes, and occasionally a new feature. Combine that with the fact that SideFX support is probably the most interactive and responsive of any other DCC company out there, and will get your critical bug fixed ASAP.
Meanwhile, Labs is adding new features every month or so usually.
I'm not sure why not having the next version is a problem, when the existing version is already extremely capable, already outperforming both the software packages you mentioned - in features, flexibility
and performance.
All this with the most accessible Indie pricing, alongside an entirely free learning version.
I can't wait to see what 19 brings, but SideFX clearly know what they are doing, and personally I'm very content to let them take their time and get things right for their next release instead of doing what other major DCCs are doing with minor updates and bug-riddled releases.
In fact, I think SideFX fell into that bug trap with 18, where it was quite buggy on release, and it took them quite a while to fix things. Hopefully, going forward they decide to scale their pace back and favour reliability over speed for their software releases.