The SmartLens 2 in 1 lens is a fun little gimmick of a device. It probably works better with a 4G or droid, where the curve of the phone doesn’t interfere with the camera. On a 3G, though, it actually worked surprisingly well for me.
The only real negative to using this lens is that you’re going to have to apply a magnetic ring to the back of your phone using the adhesive already on the ring. I haven’t attempted to take it off, yet, because I don’t know that the glue is sticky enough to put it back on, and the lens only comes with one ring. Moral of the story is, attach it to something you want to use long-term.
After that, you don’t have to worry about the lens NOT working, which is maybe not a great way to look at it. I didn’t notice a huge improvement in quality by using it, but at the same time, it didn’t hurt. It doesn’t bend the picture like the wider angle on the Bubo does, and the macro lens is decent. Sometimes it won’t work, and it’ll just be fuzzy, but if you can get close enough (often nearly touching) then you might be able to get some cool details.
The best part is, this thing is incredibly easy to put on and take off. So, attach the magnetic ring, put the lens in your pocket, and head out.