You keep saying this, some examples please .
I ain't no expert on all OSs but I do a lot of reading. I am hesitant to mention specifics when I am not an expert on the topic hence me being general before but...
True multi-tasking for one. The ability to function smoothly on minimal resources another.
And I am seeing things being implemented on the other OSs that were once ridiculed on Symbian. Again you are likely to ask for specifics but again I am hesitant to offer them as I am basing it on hearsay.
Overall I find it interesting that any one would need convincing that Symbian was a far more mature OS than anything currently offered. I would not have thought that was debatable.