I have an old peak cag, it is grand. If I was changing i would prob go for the peak creeker. Micheal bought the level 6 and it was fine too. Any cag you are going to get may leak and if it does take it back to the shop you bought it in.
Like anything you get what you pay for, if you buy one of the top brands you are likely to get a good product.
Like paul said, make sure it fits right and looks good too.
I would however take those who post on ukrgb sometimes with a pinch of salt, listen to those at home who paddle often, they are best to advise.
I do find though that a good deck is nearly as more important than a cag.
And shop local too, good for the auld economy