Both are excellent knives but different.
Firstly the Gayle Bradley. It is a chunky knife with heavy duty steel liners which are "proud" of the CF. I haven't found this affects comfort, though I did develop a callous at a hot spot in my palm:
It's a liner lock (I have had no problems with accessing the lock.) The finger "choil" is shallow compared to the stretch. I have never slipped on to the blade but I did get a small cut where my finger flesh had pushed up against the wood I was making fuzz-sticks from. Not really a criticism of the knife, just that I wasn't used to it:
Small nick:
Trying to show the grip I was using at the time of the "nick":
The CPM-M4 is great steel and should be tougher than ZDP189. It takes a great edge but isn't "stainless". The phosphor-bronze washers help give it a slick opening action and lock-up is discreetly solid, like shutting the door on a Maybach (or listening to your chaffeur do it.)
The
Stretch CF is a "big-little" knife. It has a good length of cutting edge but is much thinner and lighter, as per above posts. Thin enough to neck carry in a kydex sheath (see pic below). I like ZDP189 for all the usual reasons but I think I may prefer CPM-M4 in the long run.
The peel ply is grippy but cleans up easily enough (I have used mine for deer, foraging etc.)
(A post gralloch find of Giant Parasol mushroom: went well with the tenderloin that morning)
It is a backlock with Boye dent. No PB washers and locks up with a decisive snap, but not as "greased-weasel-s**t-slick" as the GB. The thinner handles and FFG blade don't encourage heavy use so much as the GB but mine has seen hard use without complaint.
Some comparison shots (two Stretch CF, one GB, of course.)
I like both knives about equally, but I own two of the Stretch CF (one at approx 25deg inc and the other convex) and only one GB. That isn't because the Stretch is better, I just wanted different edge geometry on each.
Summary:
If I wanted a folder predominantly for hard use: GB
For everything else: Stretch CF.
