I have the Sprint Run Delica with foliage green G10 in VG10 and the Tenacious in 8Cr13MoV. Owned both when they were first released years ago. Both are great standards, nothing fancy. Some personal comments on each:
1) Delica: The only version I like is with stainless steel liners and G10 or CF scales. No plasticky FRN for me; while being light, practical and durable, I feel it cheapens the look and feel of the knife. Not a big fan of back locks either. Back locks are proven systems but just boring in my opinion. On the positive side, if you are a steel junkie and CAN appreciate the differences in steel types, Spyderco does offer the Delica in a wide variety of steels. If you're looking at an FRN Delica you may want to compare it to a Benchmade 535 Bugout. Axis locks are fun to fidget with, plus you can easily upgrade the scales to G10 or CF offered by a number of 3rd party makers to really change things up. Yeah, there are 3rd party scales for the Delica too, but IMO they don't quite have the same effect as those made for the Bugout.
2) Tenacious: It's made in China and uses 8Cr13MoV, both features which turn off some buyers. Don't let them fool you. The Tenacious has been a big seller for Spyderco for a long time and for good reason. Build quality is very good, and the steel is very capable. I beat on mine for yard work for years and rarely clean it and it's held up beautifully. In hand, the Tenacious feels more substantial than the Delica. I much prefer the liner lock over back lock. It's not necessarily better, just more fun to fidget with. I also prefer the flow through construction of the Tenacious for easy cleaning. There are 3rd party scales available and they too can really upgrade the look and feel of the knife.
So my preference is to get the Tenacious first.
