Problem is Harry that the case is thin plastic as is the cover. If you carry this device around in your laptop bag or wherever, it is far more vulbnerable than other ebook readers. I've carried my sony around for years without any issues at all and that's because both the case and the cover are sufficiently rigid to offer adequate protection.
I don't think it represents good value for money for this reason as it costs top dollar to buy compared to other devices.
If you must get a 5 inch then I would buy the Sony for price and sturdiness even though its not so flexible.
In the UK at present though the new Kindle looks to be to be far and away the best buy both price and function wise. I have ordered one (hopefully it's wifi capabilities works a little better than the 302) and its costing me $30 dollars less to buy than repairing my 360 which was a kiss goodbye to $300
As far as file formats go, that's not such an issue as you will probably end up converting all your collection to an appropriate format(s) using calibre so I wouldn't make that a deciding factor in your choice.
The bottom line is that the 360 has a nicer form factor and offers a bit more flexibility but is far more delicate and costs a lot more