at the time I was softkicking 3.0 on my A2000 but I only ever considered it a stopgap for 3.1.
I have to admit I didn't have a specific reason to move to 3.1. To me it just felt like 3.0 was some sort of beta while 3.1 was the finished product.
With an 020 or 030, 3.1 is the end of the road - 3.5/9 should only be considered when using an 040 or better 060.
Hope this helps
Tom UK