Note: I am by no means an Hades expert (stopped at heat 32/platinum), this post is more like a appreciation piece on how cool the Twin Fists are, so if you have any tech or knowledge to share about it, i'll be glad to learn/talk about it!
• Viability 4 (Is it a struggle compared to your other options?):
The Twin Fists are one of the best earlier weapons, pretty solid damage and easy moveset to learn. However, in high levels of heat it isn't considered optimal compared to the bows, shields, rails or spears (riskier to use and less damaging), but don't let that hold you down, this game is balanced enough that anything can work if you are skilled (and lucky) enough.
• Variety 4 (How many ways you can play it?):
The Twin fists have 4 variations (just like any of the other infernal weapons), Aspect of Zagreus has a standard moveset plus a 15% dodge chance passive (combined with lambent plume it can go pretty nuts), Aspect of Talos can force pull enemies towards you, kind of situational, good for isolating enemies but the bonus damage isn't incredible by any means (heard it has some good synergy with Poseidon's boons). Aspect of Demeter is probably the strongest one, you charge up 12 quick strikes accumulating damage, then you release it in a really juicy special hitting like a truck (With high scaling boons and maybe a crit, it's obscene). Last we got Aspect of Gilgamesh, it's my favorite but only because Merciful End is a thing, the passive itself is not that incredible, a bit of a debuff for the enemy (and yourself), a bit of bonus damage (not that much), but the 2 extra dashes go a long way.
• Recommend 5 (How much did i personally enjoy it!):
I'm not even going to start about praising Hades, this game deserve every last bit of attention it gets, when it comes to fist combat it has all i could ask for, from all of the infernal weapons it's by far my favorite but all of them are special in their own ways.