I've had all three as well, but currently only own the Umnum. IMO, the XM is the best of the three if you can get one for a decent price. The 3rd gen. aren't worth the asking prices($500+) on the secondary market, but are a steal at the MSRP. IMO, the XM is worth around $450-$500, theSnG is worth somewhat less than the MSRP, while the Umnum is probably right about where it should be, pricewise. F&F is equal on the CRK and XM, while the SnG is a notch(or two) behind. My tanto Umnum was by far, the sharpest knife I've out of the three(and possibly the sharpest knife I've yet to own out of the box). The XM felt the most substantial, but I found the Umnum more comfortable in my hand. That being said, I've carried a Sebenza for over 4 years as my EDC, so that makes sense the similar ergos of the Umnum would feel better to me. I would consider the tanto SnG to have a blade that would be the most stout of the three, but in contrast, I'd also consider the drop point version of the SnG to be the least stout if that's the version you're looking at. There's no doubt the XM has a lot more "wow" to it as is likely quite a bit more exclusive, but I imagine the tanto version of the Umnum is very limited as well. I found the cut-out on the XM to be thinner than I'd like, but I also found the same thing with the SnG. Neither appeared to be an issue, but I just figure why not leave more metal there if possible? The bearing on the Umnum leaves me wondering if it's gonna stand up for the long haul, but I figure Mr. Reeve knows exactly what he's doing, so I doubt it will ever be an issue
If you could get the XM, I'd go for it, as the other two are much easier to come by, but not if it costs you a hefty secondary market price-tag. I don't really think any one of the three clearly outshines the other two in terms of real world use, but that's just me.Hope that helps and doesn't leave you more confused. :thumbup: