I've owned a LOT of cases, including the Seidio Active, Seidio Surface, Otterbox Commuter, and Otterbox Defender. I am kind of a case whore.
I would stay away from the Seidio Surface, they have been known to scratch the phones. You can google it to get more info.
The Seidio Active and Otterbox Commuter are similar and I personally prefer Otterbox. The Otterbox Commuter is $15.00 less and also has free shipping right now. I think the commuter is better put together.
From a company perspective, Otterbox stands behind their products 100% and takes pride in their cases. You can always get someone on the phone within a few minutes. Seidio makes decent products, but their customer service can be a bit shady at times. A while back, they told me on a forum that they would exchange a case, but then when I called, they said I was out of warranty.
I am very biased towards Otterbox.