From what in store staff in Currys tell me, they don't carry any e-readers in store except maybe a Kindle or two, so you have to order online. I think these days it's too niche.
Most of my reading is ePub so 8GB would be plenty, but I have around 20GB of RPG PDFs sitting in iCloud I need to start reading through, even if all I'm going to end up doing is logging them in LibraryThing. So yes, bigger is better! Besides, my ebook library isn't going to get any smaller
It looks like I'll be meeting someone in London next week to try their Forma, so fingers crossed.