We use the dog litter box, but with a wee pad in it. The boxes are a little pricey, but worth it....his aim is much better in the box...he doesn't get poopy on the floor anymore...or leak over the edge of the plastic on the wee pad. It is all contained.
We have cats...and their litter clean up is enough for me. I didn't want to scoop dog litter too. The pad thing is so much easier for us.
I have litter trained both my babies (Roscoe & Lexie). Some days they will knock it out of the box and scatter it and some days they don't. It can be messy at times. But, we liked this much better than the pads. I have 2 of the mid size boxes and 1 of the large boxes. The small size is fine for my Lexie (about 5 lbs), but Roscoe needs the large one (he's 9 lbs) so that when he does his business, it doesn't go over the sides onto the floor!!