I really like the Fenris armor, but I"m not impressed with flesh rippers. I think a good knife with with a buckler (or not for the two-handed variety) is a better choice all around than the flesh rippers. The kick is nice, but you can get the same effect with a parry, which is both easier and safer IMO. You don't have to aim a parry, just time it.

Fenris armor, on the other hand, can be your last set of armor if you don't go the eitr route. It provides enough protection to allow you to take some hits, even in mistlands, and enough movement advantage that you can easily out maneuver enemies.

its not really a good weapon long term. I wouldn't kill myself trying to make and upgrade it.
there is no high tier fist. Its main use is leveling unarmed easier. The unarmed kick is nice, so that may appeal to you.

I went to another world to farm the fenris mats I needed because my world was old and didn't spawn enough ice caves with new world generation. There's a couple seeds that have ice caves right on the starting island.

Rippers are also unique in another way: Their block armor increases with upgrades. That's not the case for many other weapons. And because the rippers' damage also affects the kick secondary attack, you can very easily stagger-lock enemies in one-on-one situations, even in mistlands.

Love the sparta kick

It is a Fists weapon, but on both hands (hence two-handed).

Flesh Rippers equips on both hands, that mean you cant use them with shield at the same time. The damage scales with Fist level yes.

The Choice is yours, the set dont have that much armor at level 4 (48), but that extra 9% ms might save your ass once. Having a good shield and a 2 set of HP food might be the best solution to that problem. So im gonna say yes, its worth it to level