I've never owned a Marfione, but proprietary hardware keeps me away from a lot of Microtechs. The few I've had have been awesome but didn't make me think "this knife will last forever and can do anything."
The Striders I have had, though... I don't know if I've owned a strider I wouldn't pit against any other "hard use" knife with some confidence. They take a beating and look good doing it.
Here's a well-used SMF, my picture:
Now, I used to steer people away from Strider because they used to be relatively crap knives. Crap lockup, crap fit and finish, crap customer service. They're reasonably respectable these days, though, and have turned around in a way that I really wish Microtech would.
I wouldn't necessarily say that either brand represents good value, though. If you want a beater knife with ridiculous steel, get a Spyderco Farid K2 or a Cold Steel CTS-XHP AK-47 (or a 4MAX now that they've been released) or a Zero Tolerance 0804CF. All of those are excellent knives that will stand up to anything a folding knife should ever be subjected to, and you could get 1.5-2 for the price of a new Strider and 3 for the price of a Marfione piece. Just my two cents on the matter.
That said, you won't be poorly-served in quality or pride of ownership no matter what direction you go in.