Hey Coxy.
The majority of humidors on the market are of acceptable quality. I believe a large quantity of them, found on the usual suspects (ebay, amazon, cheap humidors, bargain humidors, etc.) are produced by the same company. All have acceptable seals. What it really comes down to is size and style. As others have, I would advise going a lot bigger than you think. Firstly, the manufacturer rated capacities of humidors tend to be, in my experience, erroneous and exaggerated. Especially when applied to the real world where cigars are purchased in various shapes and sizes. Secondly, smoking and collecting cigars is a addictive hobby and you may find your supply surpassing your capacity very soon.
Daniel