I think it depends mostly on where you use it. I used my tablet a lot in bed, so a separate keyboard doesn't help nearly as much, because I then need to worry about holding my tablet and keyboard up somehow. That's why I've always preferred the ASUS Transformer approach as it locks the two together into one physical unit that you have to manage... much like using a laptop in bed.
It might be worthwhile to purchase it for a cheap price (you can find it for $35) if you want a bluetooth keyboard for other things too. Be aware that other bluetooth keyboards will work with it as well.