There are different opinions about Symbian here, some people want it to die, others feel sorry for its future, however my opinion is that Nokia had more issues that their operating system.
After using an N-Gage QD for several years, when it was announced the service was going to be replaced by a new platform, I looked into their new N-Series phones to replace mine.
Originally it was told that the N93 was going to support the N-Gage platform, but in the end, it didn't, I feel sorry for those who chose that model.
1) Nokia for years was unable to make their own software to work on their own phone.
I chose to buy an N95 8GB, I bought the American version because it used the same 3G band that it is used in my country, however the N-Gage software wasn't 100% compatible with the firmware of my phone and some buttons didn't worked well. It took several months for Nokia to release a new firmware yet the European version of the phone had its own version of the firmware with those bugs fixed long before. Something similar happened with the silver N95.
2) Even though all the phones were very similar, Nokia was alienating its customers by providing updates only to a certain group of people.
After that firmware update, Nokia forgot about my phone, all software updates were for the newer N96 and then the N97
3) Nokia was unable to keep old and new customers satisfied by providing them an improved experience every year, regardless of how old was their phone.
Two years later, the new N-Gage platform failed just like the original, and was replaced by the OVI store that included more software than just games. I used it too and once after purchasing one game it failed to install, I tried several times and then I got the message that I exceeded the number of installations and that I had to contact support. They took like 4 months to answer my ticket. I even wrote to The Consumerist, but they didn't care either.
4) Worst support ever.
Eventually they announced that the N-Gage service was gone for good, making it impossible to re-activate purchased games after reformatting the phone (or a firmware reload/upgrade) which I had to, so I have lost forever the 21 games I bought.
5) DRM at its worst, yet nobody anywhere talk about what Nokia did.
I don't know how Nokia can do worse with their services, the Microsoft deal looks like an improvement.
(PD: I was never able to use a N900, because they didn't release the phone with a 3G band I could use.)