I've had five (5), two (2) Mission MPS TI PE, two (2) Mission MPF-1 TI PE, and one (1) Mission MPF 3 TI PE.
Some of the older ones that were not made toward the end of John Mores (the former owner) reign are good, but trying to find one is like trying to find a needle in a haystack. Mission had lots of Quality Control problems over the years and man knives were sent out without proper heat treat either in the blade or the handle and as one can imagine it caused lots of problems. There is no real way to tell the good knives from the bad until you get one. There was also a huge problem with theft at Mission and employees and former partners were stealing knives off the line and in pieces, collecting pieces from recycle and trash bins out behind the shop, reassembling them and selling them on the secondary market. Now all of these knives are in the mix.
Beta Ti is a decent blade material and in terms of edge holding and overall serviceability is on par with AUS 8 in my experience and the experience of other knowledge individuals on this form such as MR. Steve Rice A.K.A. STR he has his on forum here. Beta Ti is a very TOUGH material you can beat on the stuff without mercy, misuse, abuse, this is your knife your not going to break it. Nor is it going to rust, pretty much ever unless you can find some boiling sea water with maybe some types of heavy duty industrial acid thrown in for good measure. To be sure the knives that were made right are very tough but will required more sharpening than say Bos Heat Treated S30V, infi, or some other higher end steels that have had good heat treat. It is titanium after all it is geared more for bend don't break than tree topping arm pit hair.
Now to wrap this up, John died a while a back God Rest His Soul, the company was sold to a new guy who owns a shop that specializes in titanium machining for the aerospace industry. He has had the company for quite sometime, made many a statement about the piss poor quality control and QC issues occurring before Johns death, then turns around and begins to sell the stock pile of poor QC knives at discounted prices. Doesn't make sense if your trying to turn the image around, but hey what do I know. This has further complicated the whole QC problem as now more poor quality knives are entering the system. It is a mess, Mission has a forum on another knife site, want to see what I'm talking about go check it out, the fanboys are in upheaval, the new owner is MIA for the most part and vendors are attacking some of the companies most long time loyal customers.
I sold all of mine after my mpf 3 which I had carried for about 3 years had to be repaired because the lock bar interface was not made correctly and the lock was wearing premature. It doesn't do me any good to buy a knife made out a material which will last for a couple of generations but has a poorly made lock that won't last 3 years of EDC. Kinda defeats the purpose of using the material to begin with, I can go buy cheaper knives that will last longer.
If they can get their act together and make the knives correctly they really have something with that material but for right now, seeing as how the new owner is MIA and not producing any new knives since he bought but still trying to sell off the old questionable stock. I'll tell you what I'm telling everyone else, STAY AWAY.