Still own both, to me they are very different beasts. The Umnumzaan is very smooth, very refined, I can carry it daily and no one really looks at it too seriously when I use it. The SMF is a thick blocky tank of a knife, mine isn't nearly as smooth and the attention to detail/fit/finish was not nearly as nice. That said I still like it, but only in the CC version, and lets not even mention what I did to that hump at the back of the handle. Ergonomics where on vacation the day strider designed that handle, but it looks bad ass. I dislike sharp edged blocky handles, and I think it might take more raw abuse than the umnumzaan, but either will take more abuse than any folding knife should be expected to take. If you think you might push either to it's limits, it's time to start carrying a fixed blade.
The SMF is larger, much thicker that would probably survive heavy prying much better, but but with less sharpened edge, in fact the SMF has probably 1/2" less edge than my Umnumzaan because of the extra finger groove in the blade on the strider. They feel to be about the same weight, but the umnumzaan feels like it takes up a lot less pocket.
Honestly I feel like the reeve is refined enough that they can justify the price (kinda), the strider to me at least doesn't bring anything significant to the table to demand the $400+ price tag. ZT for instance has some very beefy folders with similar blade steel and from what I've seen at least as good of fit and finish, if not better for half the price. There are quite a few heavy duty folders that for the $400-500 range are significantly better than the Striders I've handled (VCEP, Greyman, Hinderer if your mil/leo, etc.). Honestly I feel the Striders should be somewhere around the ZT, Microtech, price range, say $250-300.