[OhMeadhbh]

Performance, memory efficiency, some security nits (but compared to Leenucks, it's not that bad), bug fix cadence (there's a bug I filed against NeXTStep 2.2 in 1993 that was finally fixed in 2015), support (they keep changing their mind whether the command line tools are supported.)

[commandersaki]

Is there a resilient market for people using NeXTStep in the 21st century?

[LeFantome]

I imagine he means it was fixed in macOS.

[OhMeadhbh]

Yup. There's a reason that all the AppKit classes start with 'NS'.