Really enjoyed our stay. The rooms weren't huge... but it was expected. There was wifi, and also a ethernet cable, as well as a 115v plug available in the room. We only stayed one night due to a layover, but the KAL bus took us right infront of the hotel, and the subway was conveniently located downstairs in the building. The buffet restaurant naru (?) was excellent but quite pricey. No complaints.

We stayed here for 5 nights in late October 2012. Lotte City Hotel Mapo is a quiet understated higher end business hotel located in the Mapo-dong area of Seoul. Our room was modern and elegant, spacious, very clean and quiet and had a view of the main intersection and surrounding buildings.
Pros:
The beds are comfortable and linens very nice.
The bathroom was large and had a separate shower and tub. The rain shower head is a very nice touch.
The pool and gym area are very nice amenities and so is the self-service laundry. It makes it easier to pack less if there is a laundry facility.
There is also free internet which was great to have.
The staff is very courteous and professional.
The hotel is very convenient, the airport limousine bus from Incheon drops you off in front of the hotel. Other reviewers say it's far away from things though in my opinion not really. It is located with 2 subway lines connected underground so getting to the major attractions in Seoul in 20 minutes or less. There are also shops, restaurants and a Lotte Market downstairs that you can pick up coffee, pastries, drinks, dinner, if needed.
Cons:
Not really any.
If you want a reasonably priced higher end stylish business hotel in downtown Seoul then this hotel is an excellent option.

Hotel middle range with nice situation. But room too small, very simple, bad TV, bathroom without space and enough facilities. Kind service but little experiences and limited efficiency. Breakfast too limited.

Stayed here for 3 nights Oct. 2012 as tourists from the Philippines. I picked this hotel mainly for its reasonable price, good reviews, nice looking rooms and connectivity between subways and buses. Satisfied my expectations pretty much, they allowed us early check-in, gave me the room type I preferred. The basement arcade with the supermarket and food shops were very advantageous. Didn't have problems communicating with the hotel staff in English. We took the regular airport bus (6015) going there then the KAL limo bus (6702) going to the airport, no hassles at all despite our heavy luggage, the bus stop was just across the hotel, no issues crossing the large intersection because of the pedestrian lanes. Overall quality was great, thanks to the Lotte brand. Thanks to TripAdvisor and it's contributors as well.

For the cons: these are relatively minor issues: Pillows were too soft, I had to fold one up so I can get the right cushioning for my head. Nothing much to see outside the hotel, didn't bother to roam around the area. It's a business hotel, so don't expect full service.

I recommend this hotel to anyone looking for alternatives from those rather expensive ones with smaller rooms around Seoul. I highly consider going back the next time around.