In the case of C#, there are very lengthy docs and StackOverflow threads on how to properly use IDisposable -- what you need to use to clean up non-GC-able resources. A great many classes in C# libraries use IDisposable, so outside of pure business logic you end up with a lot of 'using' blocks. I've written a lot of C# code that needs to clean up external resources using Dispose(), and I've had to fix a lot of C# code written by people with a poor understanding of IDisposable and how GC actually works (eg. useless GC.Collect() calls everywhere).

So I think the benefits of deterministic object lifetimes, and it being easy to explain when each object will get cleaned up (all of it, not just the memory), outweighs the marginal benefits of heavyweight Garbage Collection.