I looked at EQ5 and EQ6 before I bought my EQ7. The programs all sound good. One of the hyped features was the new fabric library - but for me that is not that important. I don't get that specific with my quilt 'playing'. The only reason that I HAD to go with EQ7 was I got a new computer earlier this year preloaded with Windows 7 and was afraid that any of the older versions would not run on my computer. I have had that ALOT with W7.
I started out with the original Quilt Wizard as my 'trial run' software. Love the software but not it's limitations. I really wanted to be able to draw my own blocks. So EQ7 was the right choice for me.
If your operating system will support it, I say go for it. If it doesn't work right for you then you can probably see it again. There are a few listed on eBay and EQ5 and EQ6 really seemed to go.