while the debug allocator can tell you at runtime about use-after-free or memory leaks, that's a less strong guarantee than rust or a GCed language
there are no closures; in general the code you write is lower-level than code in python, c#, rust
the language is very new
--opinions of a zig dilettante
bonus observations:
the std library code is very readable
the language overall has an excellent philosophy & design approach, and i predict it will become extremely popular
(as a single point of comparison: even after puzzling over it for a while, i still don't understand how modules work in rust; the equivalent feature in zig is immediately obvious, and in fact is the same concept as structs. how cool is that? (very cool, imo.))