Is it safe to go to South Korea now?

Not a safe place at this time. Wait a few weeks and watch the news.

No never go there

Everywhere is not safe in South Korea. 14 persons were dead, and 138 persons are infected by MERS at June,the 13th,2015. The Korean Government behave to control MERS, but cannot control MERS.　The South Korean government have been sprayed with insecticide DDT across the country.（See the following photo.) However, whether DDT is good for MERS virus?
Universiade Gwangju tournament is scheduled to be held from July the 3rd. Korean Government will have to decide to keep the schedule or not. This is a check point what Korean Government is thinking.
MERS would keep its power for a few years in South Korea.

There is MERS but it's being blown up by the media just like Ebola was being blown up in the US. You'll be fine.