They are both great knives but it all comes down to use and application for the specific owner.
I'm going to assume your use is ADC and perhaps defensive.
Lock: Endura (I hate lockback knives but i have to admit that they are stronger than linerlocks in most cases. A linerlock is easier and safer to operate with one hand in my opinion)
Price: Tenacious (30-35) over the Enduras (50-60) These prices are based off of your specifics.
Materials: Split. The Tenacious has a better handle material (G-10) over the Enduras cheap-feeling handle material (FRN) [FRN is quite strong, don't get me wrong. Just makes it look like a flea market knife] The Endura however has a VG-10 blade steel as opposed to the Tenacious's 8CR14MOV. The latter is by no means a bad blade steel but in my experience and opinion, VG-10 takes it easily.
Weight: Endura (3.6 oz) Tenacious (4.1) Very nominal difference... to the point where i would just dismiss the category but some people are very picky about weight.
In the end my opinion and recommendation would be the Tenacious. Why? Price is almost half, still a good blade steel, better handle material (Not to mention the steel liner that adds a bit of strength), Blade shape is better in my opionion, and the lock is easier and safer to operate.
It's hands down for me, i knew the moment i read the question, but i just wanted to set forth some facts to help you decide for yourself.