I have the educational version of Sibelius 4 and I was wondering if people thought it was worth upgrading to Sibelius 5?

I'm not. The new bits aren't so important to me.

Welcome to the forums!

I am currently using Sibelius 5.1 version. It is just nice to be used!

I believe that there is not much difference between 4 and 5. I have just ordered 5 myself yesterday but I was using 2 before that. Perhaps hold out and upgrade to 6 when it comes?

I upgraded from 4 to 5 and there only seems to be one main difference - you can have an idea bank. So you can take snippets/phrases of a work and put them in an idea bank and use them later in the composition. So great for composers, not a big deal for most other people.

It has a nice bit of music at the beginning too

I ended up having to upgrade to 5, because I couldn't get 4 to work on my new mac. Have been pleased with it, welcome change of opening music (sad I know lol) and nice interface, having said that, using anything on a mac is different to pc so it was always going to look and work slightly differently from 4 on my pc!
Find the sounds are much better, and there are a few new shortcuts that I have found, which I may just have not known about on 4 but pretty sure they weren't there...
Sorry not much help!