I spent 6 years slogging through Symbian work. The whole "C++ but not quite" approach was infuriating, and the system level API's weren't much better. It was very difficult to work with. The original iOS SDK felt like a revelation in comparison.
It was probably the best phone OS at that point in time. It was just a little too late for Nokia and they disastrously threw their lot in with Microsoft.
It's funny that BB10 was in many ways similar to MeeGo, it also used Qt/QML and had a similar UI. I went to BB10 after wanting the next closest thing to the Nokia N9 I had before.
BB10 was QNX-based, otherwise I wonder if RIM and Nokia could've pulled their efforts along with other big guys (Samsung and Intel who went on to do Tizen) to set up a compatibility layer between their respective platforms to allow an app ecosystem to flourish.
MeeGo was nothing like Symbian. It was a Qt/Linux stack and quite sweet in many ways. N9 was the only phone I ever owned that got me excited.