mho - at the moment I don't know what I want/need from the bag. I've only had the lens a day, and obviously it doesn't fit any of my current bags! This lens has been a big outlay (for me) and I doubt that I will be changing it ... so I would like to get a good bag for it first time.
I know what you mean, Ask your self a few questions like these,
Does it have to meet airline carry on size.
Does it have to enable the hood to be in shooting position,
Does it have to carry a tripod / monopod on the outside,
Does it have to allow full frontal access or just top access,
Is uk customer support a priority,
Does it have to be a semi rigid construction to protect the lens,
How good does the back pack feature have to be,
Do you want a fully removable backpack feature,
Does the bag have to enable very quick access to lens,
This is the sort of things i would be asking myself, depending upon your answer to quite a few of these will indicate instantly that the lowepro is not the bag for you, as it isn't a feature of the bag.
If your ever around Sheffield your more than welcome to have another look at a kinesis L621 + backpack harness - kinesis have now replaced it with the longer L622.