They are relatively low spec too, from engadget:
The 6.3-inch model has an 'HD display' (we're chasing the precise resolution, though it's likely 720p) alongside a dual-core 1.7GHz processor, Android 4.2 and an 8-megapixel camera. Software features like Air View, Multi Windows, Pop-up Play will make sure you have plenty to do on that giant screen. The Galaxy Mega arrives somewhere between Samsung's Galaxy Note 8 and Galaxy Note II, although we're hoping it'll be priced slightly more humbly than either neighbor. The Galaxy Mega 6.3 houses LTE and HSPA radios, while you'll get GPS and GLONASS to aid any location-based antics. There's a 3,200mAh battery and internal storage that can be expanded by microSD up to 64GB, with 8 or 16 gigs (there's two models) built-in to begin with.
The HSPA-only Galaxy Mega 5.8 reduces the size -- and pretty much all the other specs. The resolution drops down to qHD (960 x 540), while it packs a lesser 1.4GHz dual-core processor. It has the same 8-megapixel camera, while the smaller, er, Mega, only comes as an 8GB model.