I worked at the company which used a proprietary compiler, IDE including debugger.. It was few thousands $ I believe. plus about the same amount for their proprietary JTAG adapter.

Worst software I ever used. Crashy, slow, critical features missing (example: debugger can show thread list... but not the stacks of other threads).

So no, I would not expect expensive commercial software to be better. It might generate 2% faster code or be certified, but the day to day experience would be terrible.