I asked this question to the team at Fusion, I ended up paying the extra for the Urban. Have had it about a month and have been meaning to start a thread to rave about it, as this is without doubt one of the best gigbags available.
Really, it is great. I'll get it done and get some decent photos up.
Top quality products and customer service. I bought this to replace a Protec Contego, if the Contego is very good (which it is) then the Fusion is amazing. It manages to be compact but will lots of usable storage, great quality materials and zips, rain/antitheft cover included and the removable 'collar' is a top idea. Plus, very good protection yet nice and light.
Anyway, here is the response from Fusion:
'I have been in the warehouse to compare the bags myself, and there are a lot of advantages to the Urban Bass Guitar bag.
It is a more generic shape and will accommodate various sizes of guitar. Although the padding is 20mm compared to the 30mm of the F1, the Urban comes with a removable 20mm high-density foam collar, allowing you to mould it round the instrument thereby giving it 40mm of protection and maximum stability, although the guitar will still be very well protected without it.
There is a removable headstock block, which can be positioned wherever it's needed. The base of the Urban bag is rubber, the backpack straps tuck away inside specially designed pockets and the overall material is of a higher quality. The Urban bags also come with a raincover and are lighter in weight.'