As far as I understand it, 420HC is a mid-carbon stainless steel that gets to be around 55-59 Rockwell with proper heat treat, which is perfectly acceptable for a blade so long as it's heat treated correctly. 420hc is tougher than 440c and holds up better to abuse, it's just doesn't get as hard as the other alloy.

440c or Nitro-V or AEB-L all get up into the 60-65 Rockwell hardness, but for a carry knife or utility knife 420hc is a good choice because at the somewhat lower hardness its easier to sharpen and can withstand greater force without breaking

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>Muh magical super steel
Beware of the supersteel shills. High edge retention often lead to lower toughness/durability. A lot of the meme steels are also brittle and prone to chipping.
99% of a knife's performance comes from the geometry, and heat treat. 1095/420HC/440C with a good heat treat, and proper geometry will match any "super steel" performance any day of the week, and twice on sunday.

Steel composition matters but so does heat treat. I'd rather have a Cold Steel AUS-10 heat treat than S90V with a crappy one. Also consider the blade size and weight, toughness beats edge retention. Buck does heat treats for a surprising number of knife makers, and that's because Buck was one of the first in the industry to perfect, industrialize and market knives based on high performance due to superior heat treatment. 

Ontario MK3, OKC3S, AK Bayonet, M9 Bayonet, Glock 81, Kobun, Ka-Bar