I would say mainly to look the traffic policy for your needing
If you are heavy user or not
Every one now has traffic policy so it de-pence what use you will do
It may be worthing less money if is big difference
http://www.virginmedia.com/images/table_30mb_800px2.jpg
Now your area is been upgraded, the upload speed with XL 60 from 3mb soon or sometime later will be 6mb so your previous upload for you was 5mb.Still about same level as before
My opinion is all about traffic