I checked out the Canon version before buying this. I couldn't justify spending $300 for a battery pack so I bought this one. Not disappoint. It works great and at 1 10th the price you can't go wrong. It appears that the weather deal isn't as good as the Canon version, but if you don't plan on using your flash in the pouring rain it should be okay. Delivery was fast. Less than a week to receive my order.