I've used both and am completely hooked on the Austrian scythe. It's not flimsy but is much lighter, so you can do more. Also you can sharpen it with a wetstone, in the field, so it stays sharp and therefore cuts better. An English scythe has to be sharpened with a grindstone wheel so you either have to set up a treadle one in the field or work with an increasingly blunt blade as the day goes on.
I've got a 'ditch' blade on mine and it's dealing with two year old, head high dockens and nettles easily, but will also cut rough grass and seaves (rushes). Ordinary grass and wildflowers need a grass blade.
I didn't look where you are. The Scythe Shop online sells them, as does Paul Kingsnorth in Cumbria.