Having owned a blur, a manix 2, and an endura, here's a little chart for you based on my opinions and experiences.
Blur
Pros:
KAI does a wonderful job with elmax
Decent ergos
Very grippy with the inserts.
Ramped thumbstuds--so much better that any other type of stud
Can be deassisted and works well that way
Cons:
Thumbstuds--Ramped are the best version of thumbstuds, but I prefer holes and flippers
Metal handles--cold in the winter, hot in the summer.
Recurve--can be a pain to sharpen depending on your sharpening method.
Linerlock--My least favorite lock
Assisted--a solution for a problem that doesn't exist
Right hand only clip
Endura
Pros:
Good ergos
ZDP-189 is one of my favorite steels, I have two spydies in it myself
Ambidextrous with the back lock.
Spydie hole
Ambidextrous clip
Cons:
Size--larger than the other two
Backlock--though ambidextrous, not the strongest lock, and has been known to develop vertical blade play from what I've heard
Manix 2
Pros:
Best ergos of the bunch
S110V is supposed to be a great steel
Ball bearing lock--one of the strongest locks in the biz and ambidextrous
Best blade shape (again, IMO)
Spydie hole
Cons:
BBL is very stiff when new
Jimping out the wazoo--enough to please the guys in W&C