I have used both Aspect and Symposium.
My personal favorite is Aspect, and will not move to Symposium if I am already using Aspect.
Nortel is known to be difficult to administrate.
Just take the call routing programing as an example. In Aspect you use GUI CCT to create your routing rule. Simple, easy to see, and easy to learn. A new person can be trained and can handle most common routing within a month. Symposium routing, still CLI base. You need to familar with most of those command wordings in order to has a good feel of how to set the routing rules.
Aspect, you can administer everything from the Management software. Setting up trunk group, call routing, restriction, agent, ..... However, in Symposium, you can only set agent, skillset, routing script. Other related programming is from M1 administration like trunk, phoneset, etc. M1 administration is even harder to learn.
You can take 2-3 courses from Aspect, and can be very comfortable to do the administration work. Using M1+Symposium, you need a lot more. An example is you need to take 3-4 M1 course from Global Knowledge/Nortel in order to just know how to program the phone set.
But the most important part I don't like Symposium is the reporting capability. Symposium database is structured in an interval base. You can have interval (every 15 mins), day (one day), week, and month "view". You cannot seperate each individual call's information. Think about the shortest interval view, all the calls are summarize within 15 minutes interval. This means you cannot get the CLID or ANI of each call. The only place you can find CLID in Symposium is the eCallbycall stat, that is like the callevent today table in Aspect. In order to get the same flexibility of report creation as Aspect do, you actually need to build by yourself another replication database server for Symposium to dump the eCallbyCallstat and create your own tables and collapse that monster data into different useful summarize table. A huge job.
