Both very solid bindings. Two of the best bindings on the market really.
The deadbolt 15 (which is the same as the tyrolia peak/head mojo/amplid ect) is probably the best binding for its price on the market. It's an incarnation of a tyrolia race binding so has lots of metal, great retention,ect. It's probably my favourite binding after fks.
STH16's are also bomber. Not quite so much as the older 916, but it's a lot lighter, and is a good compromise of strength/weight ratio. Also has toe height/toe wing adjustment ect so good to get a flush fit with worn or old boots.
Buy the cheapest one, you will be happy with either. This is of course all assuming that you are the right skier type for a 15/16 din binding. Deadbolt is 5-15, and STH16 is 9-16.