Modern Smalltalk-style languages can be fast. Look at Javascript! And in Obj-C, you can drop down to plain C when you need the speed.
It's possible to get your types mixed up when using non-generic collections, and that will throw an exception at runtime. No different from Go or Python.
In terms of memory safety, it's a step up from C if you use ARC, as all your object lifetimes are managed automatically. You can still get memory corruption if you're careless with arrays, but it's not really an issue with objects.
Modern Smalltalk-style languages can be fast. Look at Javascript! And in Obj-C, you can drop down to plain C when you need the speed.
It's possible to get your types mixed up when using non-generic collections, and that will throw an exception at runtime. No different from Go or Python.
In terms of memory safety, it's a step up from C if you use ARC, as all your object lifetimes are managed automatically. You can still get memory corruption if you're careless with arrays, but it's not really an issue with objects.