I'm a hardcore Benchmade fan; but recently grabbed a manix2 XL while I continue the hunt for my missing Onslaught 741. I have to say... Thus far the manix has proven superior in every way. I understand that the 741 is not the 275, but there are many similarities for the purpose of comparing to the Manix2XL. Little things, like the G10 on the Manix compared to that of the Benchmades, the bolts, the ball bearing lock; all look and feel much sturdier. The bolts on the Benchmades, for example, are little T6 round head bolts (one of which I quickly and easily stripped out using a cheap torx). The bolts on the Manix are maybe T8 at the smallest, and flat. Little things like that. There are certainly things about the Benchmades which are more aesthetically pleasing perhaps (of course this is subjective), but every little detail of the Manix just screams durability and utility. It is my understanding that the ball bearing lock is significantly stronger than the Axis. It feels stronger, but could just be that it isn't broken in at all.
Aside from these things, you are really comparing a D2 saber to an S30V FFG. The D2 is going to be negligably stronger, noticeably more difficult to put an edge on. I have never had any issues with corrosion in D2 (it actually has one of the highest Cr contents of any tool steel). I ultimately prefer S30V. It is a blade metal from the ground up. I also prefer a FFG (much easier to maintain an edge on).
As stated above, ultimately an objective stress test would have to be applied to each to determine overall "toughness"; but for my money, and it pains me to say this, the Manix is a superior cutting tool to my past Benchmades.
P.S. An important note for me personally, the MSRP on the Adamas is considerably higher for a blade formed from considerably cheaper steel.