Do you want a tough-as-nails flipper or a tough-as-nails manual folder?
Long, thin blade or shorter, fat blade?
I wasn't super impressed with the XM-24 I picked up in a trade. The detent was weak and nothing seemed to justify the expenditure. An SMF, however, will cost less and be just as hardy. I don't really like either folder, but I like a lot of the aspects of both. If you're torn, look at the Microtech DOC. It's a flipper SMF, essentially, with a price tag about 1/2 of the other two options. I'm even selling a lightly used one if you want to grab one on the cheap to check it out.
I will say that I would trust the consistency of quality control from Hinderer more - better pivot action, lockup, centering, etc - but I would also argue that the SMF is a folder that is designed to destroy worlds and centering seems to be less of a concern when you open a folder and are convinced you could split Mt. Everest in half with a well-placed stab and have done no damage to the knife.
Hinderers make me think of fine watches. Precisely machined, durable, oozing quality, and... Way more expensive than it needs to be. I won't say the price isn't justified to some degree, but given that it's a cutting tool, I could buy three or four ZTs with very similar QC, a much better and faster warranty service, and identical / better materials...