I picked up a Manix 2 LW a couple weeks ago and it's fantastic. The one I received has a riveted pivot pin (the latest revision has a torx screw in its place) but the factory-set tension is absolute perfection. The lockup is perfect in every direction and the pivot smoothness rivals literally any of the smoothest knives in my collection (some costing much more). The CTS-BD1 steel is pretty new to me (I now have two knives in this steel but I've not owned them long), but I have read nothing but good things about it. It's certainly not considered a premium steel by most enthusiasts' standards, but it sharpens quickly and takes a keen edge. After some light stropping, my Manix 2's factory edge is even finer and I'm very happy with it thus far.
That said, I have always loved the Endura and have owned at least one Endura model for almost ten years now, beginning with a stainless steel-handled model and eventually a few FRN. I carry my FRN Endura 4 FFG at least one day a week from my knife rotation and it's beauty and simplicity is always readily apparent. Spyderco's VG-10 is one of my favorite steels. I've never had any issues with rust whatsoever, it sharpens easily enough and holds a sharp edge for a long time... in my personal experience, its edge retention comes close to my S30V blades and it goes for long stretches between full-blown sharpenings. A brief stropping now and then and the VG-10 is back in business.
Both knives are fast to open and close and the feel of the handles are pretty similar, in terms of quality and grip. I find both to be extremely comfortable, both while cutting with them, as well as how they feel clipped in my pocket. The Manix 2 LW's handle might feel a little more "toy-like" due to its stiffer composition, but I trust it to hold up over time and wear well. The Manix 2's caged ball lock is a lot of fun to open and close and that earns it a couple extra points in my opinion. You can flip the blade in and out of the handle by simply pulling back on the lock and giving a small flick of your wrist.
Really, they both fill a very similar role in terms of blade length, grind, and overall utility. Don't get too hung up on the steel types. In fact, as someone who owns and really enjoys both models, I would recommend basing your purchase on what looks best to you; watch some videos and see which looks like it would be more comfortable in your hand and in your pocket, and which might match up best with the tasks you intend to complete with it. For me, they're so similar in function that it's almost a coin-toss. Lastly, consider the price. Depending on where you buy, the Manix 2 might run you as much as $20-25 more than the Endura. If every dollar counts, go with the Endura and never look back. You will still have ended up with one of the finest low-cost knives to ever hit the industry. If you've got the extra ducats and wanna try the caged ball lock, you can't go wrong with the Manix 2 LW. Super fun and expertly designed.
Whatever you decide, be confident in knowing that, simply put, Spyderco doesn't make junk. I'm certain you'll enjoy either model.
Go with your heart!