"The compression lock and back lock are Spyderco's strongest. The Lil' Temperance seems to be the strongest Spyder that over time does not develop any blade play."
I'm not sure I would agree with those statements. The Lil Temp is good but I think the Manix is rated as a stronger lock by Spyderco.
Nobody mentions the ball lock but everyone I have had had ZERO play and were quite solid. The D'Allara Drop Point is a heck of a knife for the money. It cost about $60 steet compared to about $110 for the Manix. It is not as good as a Manix but if price is a real issue, I think it is about as good as you can get if you need a strong Spyderco. No corners were cut in quality, just materials. It is FRN not G-10 and it is VG-10 instead of S30V. Still, it is a solid knife for not a alot of cash. If you break this one, you need a fixed blade.
But, like others have said, the Manix, Mini-Manix, Lil Termp, Chinook, Military and ATR are quite strong. Here are a few other strong ones: Endura 4, Delica 4, D'allara Rescue, Spyker and Para Military are pretty good as well. My choice would be a Mini-Manix or a full size Manix if I were going to use it hard. My Manix is my camping knife but my new CF Military is my everything else outdoors knife if that tells you anything. Hiking or backpacking, I will take the Military, for camping only, I like the Manix. Really, either one could do any job but I like the light weight of the CF Military if I am just hiking around.