Depends what you want to do with it really, the Samsung has a bigger "technically" better screen while being smaller overall and is lighter. They are both good performers, but would give the hardware edge of course to the Shield. Both have expandable memory.
The Shield is cheaper (16GB wifi options) and is quicker to get updates and is more stock Android if that is a factor?
For me the Shield is the better bang for your buck, cheaper, basically stock android, no physical buttons (on a tablet is a big deal...phone I can deal with)