for me, my lips feel much different b/w lip conditioner and tendertones, here are my opinions:
-lip conditioner--fab feeling, makes my lips so soft and moisturized. little/no colour but thats fine. usually use it before bed, also if i don't want lip colour but moisturizing (though i believe you can also apply this, then lipstick on top)
-tendertone--little/no colour payoff on my lips (different colours don't seem to show up much different on me IMO). makes lips look glossy. I do not feel the same conditioning/softness I do as with the conditioners.
I'm getting much further down with my lip conditioner than with my tendertones. I like the conditioners much better, but of course I'm sure others have opposing feelings!
to me, it doesn't hurt to have one of each