Would rate it a 3.5 or a 3.8, but rounded up.
Pro's: Prime location, right at end of Myeongdong shopping district. Close to shop but far enough so not too crowded. Short walk out of exit 3 from Line 4 - literally can see hotel from the subway exit. Spacious room with fridge. Lobby has refillable cold water, ice, hot water and microwave if you want to heat up leftovers. Shower and sink water pressure is amazing (almost too painful at times). Also, free umbrella available to use by the entrance during rainy days - so don't have to buy one.
Con's: Old/outdated. No USB-C chargers. AC in our room is spotty - weak and only works for short stints before it turns off. The light control for the room was not explained to us - it is all controlled by a device next to the bed so it was confusing the first night figuring out how to turn the lights off. Bathroom was a bit dirty, water keeps leaking thru shower doors despite how many towels were on the floor. Mold on the ceiling of the shower. Also rainfall shower fountain had a bunch of rust, mold and possibly green algae on it as well so avoided using that. Bare amentities for bathroom - soap, shampoo, body wash. No conditioner, no vanity set. No toothbrush/paste without a fee. Since I was on 2nd floor, can hear the busy streets and cars throughout the day/night when window were open so hard to sleep past 8am.
Overall, great place if you need a place to crash if you are out in the day a lot but don't expect anything spectacular.