Positive:
I would go with my Spyderco Foliage Green UKPK. Bought it just to have a legal EDC for the U.K. After I started carrying it, I realized that for 95% of my uses, a slipjoint of this style is all I will ever need. One hand opening, finger choil to prevent accidental closure, and still tough and light weight. Started a little mini obsession with Spyderco Slipits for me.
Negative:
Buck Knives in general. I have owned four or five Buck Knives over the past few years, and every single one I have bought has had terrible fit and finish. All have unfinished edges, gaps in liners, badly mismatched edge grinds, off center blades, or incredibly weak springs or super hard to open nail breakers (for the slipjoints). I kept giving them a chance due to their low price point, and generally positive opinions on the forums, but I regret every Buck I have ever purchased. *Correction* Actually, the Paklite Skinner I got from Walmart was pretty good, so maybe its just their folders that are junk.