Upbit exchange is one of the biggest exchange and its trading volume is also very high from when its listed on coinmarketcap. Traders can trade quickly because of high liquidity. Upbit exchange supports more than 200 cryptocurrency trading pairs and also Upbit exchange accepts fiat currency deposits in KRW from south korean banks.
User can't purchase cryptocoins with fiat currency by credit cards through Upbit exchange. Upbit provides multiple trading pairs but most of them are with KRW pairs and very few pairs are with BTC.
Upbit cryptocurrency exchange support system is disappointing because there is no responce from support on my ticket yet. Upbit exchange trading fees is also low as compared to other south korean cryptocurrency exchanges. Upbit exchange does not offer margin trading feature to their users.
In short, upbit exchange is best exchange for south korean people that provides the fiat currency support in KRW and high liquidity but upbit does not offers many features like margin trading and purchasing coins with credit cards features.