I usually only use these 2 apps to navigate around Korea and I manage to get through with not much problems. They are Google Maps/Kakao Metro. To me, Naver Maps and Kakao Maps have slight differences so you can make your choice.
Use Kakao Maps, as they provide more options to choose from. Google map is good for real time updates.
I will choose will be dependent on the time taken, number of transfer, the number to walk to the location from subway/bus stop and the cost.
I did a search of travelling from Hongdae Station to Myeongdong Station.
Kakao Maps provide more options to travelling to Myeongdong Station.
The subway option for Google Maps only have 1 option which is taking Line 2 and take a walk to Myeongdong Station. To walk to the actual Myeongdong station, it will take around 10 minutes.
Google map also provide the bus options but is only 3 options.
Google Map
For Kakao Maps, I have a total of 15 options.
For the subway options, there are 4. I can choose between changing Line 2 to Line 4 and it will be a 1 minute walk. For the direct Line 2 option, I will have to walk around 10 minutes.
They also provide information of how much the taxi ride will cost which is around 10200 Won.
Kakao Map
If I making a trip to Myeongdong with a group of 4 , I will considered taking a taxi as it is not that expensive as subway will cost 5000 won for 4 people. However, it will during off peak traffic as it do not like to stuck in a traffic jam. It is not always easy to get a cab. I had difficulties getting a cab back to Myeongdong from Hongdae at times. There is not much time saved, but your tired legs will get to rest.
I will not be taking a bus for this trip as the time taken is almost double. There are times, bus is the more direct and convenient.
For the subway, I have 2 options. I usually take the direct Line 2 ride as I do not mind walking but I dislike stairs.
However, if the weather is bad. Taking a Line 2 to change to Line 4 to reduce the walking seems a much better idea.
You can also check out the walking option with Kakao Maps, this will take around 1 hour plus which is highly not recommended. Some places are really close, for example, Namdaemun market is like a 10 minutes walk or a train station away. It is more feasible to walk then taking the train as the time taken is the same.
Pros and Cons
Subway: Easiest to navigate because you cant miss a stop with the signs and announcements. But may have to climb a lot of stairs. There is a need to walk 5 to 10 minutes to change from one line to another inclusive of stairs. Sometimes, I choose the option that take a longer time but with less transfer as it is tiring to use the stairs.
Bus: It is more interesting as you can enjoy the sights of Korea. It is sometimes more convenient with less walking compared to subway,Is affected by traffic condition. It is hard to get track of the which stop you are at because some stops are missed. If you missed a bus stop, you may need to walk a lot to get back to your location. I will try to avoid it if there is peak hour traffic and also more than one transfer.
Taxi/cab: You may not get one when you want to get. It is affected by traffic condition. There is also quite a number of touters and dishonest taxi driver stories. It will send you to the place that you want with minimum walking. The price can be quite steep especially if there is only 2 person taking the taxi.
Walking: Good Exercise, can eat more.. Will get to see Interesting things sometimes. Will be tired out before reaching the place. It is better than changing subway lines which includes walking and stairs. May get lost. May walk to places that you are not supposed to be at
Using Google Maps for Real time update
I tried to use Kakao Maps to navigate my way around, but they don't really have real time update. I have to keep refreshing the map to see if I am moving in the right direction or whether I am reaching. They don't show me the right direction to start at times. However, they offer more bus/subway options compared to Google Maps at times. It is worth checking out to see which is the shortest route to your destination.To walk with google maps, I will just randomly chose an options after inputting my route.
Zoom in. I have to make sure my ray of light face the direction I am going.. Then I will start walking in the direction of my intented location. I will constantly check my map to see if I am walking in the right direction. Check constantly as you do not want to realise you are in the wrong direction after 5 to 10 minutes of walking.
This can used for bus and taxi too.
I was taking the bus at Ulsan, we have no idea where to get down and we had some communication problem. When I saw the blue dot reaching my intended location, I press the bell to get down.
I used this for my taxi ride to make sure my taxi is heading to the correct direction.
I am reaching my intended location so I can get ready to get off.
The negative about using your own assume walking route, you may get to some quite quiet and dark places or walk past some expressway which will be a challenge to cross.