I see that this same thread has been posted over in the BM sub-forum, so I am going to put my answer here in this forum and I'll explain why. I choose the Contego over the Gayle Bradley and I think that more people will recommend the GB here in the Spyderco forum and more people will recommend the Contego over on the BM forum so I'm choosing to mix it up a bit.
I own both knives and consider them to be in my top 5 knives that I have ever owned. Primarily, I love the M4 blade steel. It, along with CTS-204P on my Southard (which is my favorite knife), are my two favorite steels. Being able to cut all day long without having to stop and sharpen is far and away my number one requirement in a blade steel. Even though I live in Miami, I choose high wear over corrosion resistance every time. I use my knives enough that corrosion just hasn't had time to form on the blade. My Bradley looks brand new and my Contego has a black coated blade so corrosion on the M4 is a non-issue.
To me, the main thing that differentiates the Contego from the Bradly and why I recommend the Contego over the Bradley is a simple one, although my criteria probably won't help many people. I really love the aggressive nature of the Contego with regard to ergonomics. This seems to be a love or hate thing with most people, I never hear anyone say that they have no opinion on the grippiness or ergos of the knife. It's always one or the other. Personally the Contego fits my hand perfectly and it stays locked into place. I haven't noticed any hot spots under heavy use and I certainly haven't suffered from any slippage so to speak.
Some secondary observations that I've made between the two are as follows;
I prefer the axis lock over a liner lock, but have no problems with the liner lock in general. The nature of the Bradley lock access is such that it was designed to make it difficult to accidently unlock the blade. This is fine, but it just makes the axis lock easier to actuate one handed.
For both knives being similar in weight, I like the fact that you get more blade length and hence, more blade usage out of the Contego than the Bradley.
I think that the Contego is thinner in profile from top to bottom when closed. I notice that it is slightly easier to slip my hand into my front pocket to get my keys out with the Contego clipped in rather than the Bradly. It seems like the Bradley just takes up a little more space when clipped in.
So these are the reasons why I recommend the Contego ever so slightly over the Bradley. For the ergos and grippiness, this is wholly personal, the Contego works for me but may not work for you. Blade length is important to me and I have no restrictions so I carry the biggest one that is still comfortable for me. Knife profile and ease of pocket access when clipped in is really the differentiation that may help set one apart from the other for most people.
All that being said, I still consider both knives to be pretty much equal as far as joy of ownership. I love them both dearly and would not hesitate to immediately replace either one of them if they were to get lost. And as far as where they sit on the list of my favorite knives, they are right behind my Southard which I believe to be one of the finest production knives for sale today. The Southard truly is a spectacular piece in every way (except for that horrible brown scale), but this thread isn't about the Southard is it?