Source - currently stationed in Korea. Been here for 2 years. Stationed here straight out of d school.
Korea isn't hard to get, as a lot of people will actively try not to get stationed here. Also, spots open frequently given the annual turnover rate. That being said, some things are changing. Due to some shenanigans with people jockeying to get to and stay in Korea for their whole careers, the current CO has made some changes.
-HRC is limiting if not eliminating the opportunities for first tours in Korea
-extension is only going to be approved the first time. ie, 1 year can become 2 (or 2, can become 3 w/command sponsorship) no more after that
-Command is not authorizing in country moves. once your in a clinic, you stay at that clinic
All that being said, let me answer some of your other questions. Korea has 9 clinics
-3 up near the DMZ: Camp Casey, Camp Stanley, Camp Red Cloud
-3 in Seoul(Yongsan): DC2, DC3, Carrius
-1 just south of Seoul: Camp Humphreys
-2 in Daegu - Camp Carroll, Camp Walker
where you go is entirely subject to which clinics need people. now, a lot of our clinic activities are going to be transitioning from Yongsan to Humphreys. They're building a huge new clinic, and it should probably be up and running within a year. As such, they aren't really assigning that many people in Yongsan anymore. As far as getting a spot, doing a 1 year wont really have any effect on your chances.
Now, considering all this, a few things about life here
Pros:
-Fantastic travel opportunities
-lots of small clinics, which is the biggest determining factor in whether or not you'll get to practice with much variety. AEGD 1 yr grads still work the amalgam line in the bigger clinics.
-great opportunity to live in a new & different place. experience a way of life that isn't your own
Cons:
-far from family
-we're dual tasked as a field unit (DENTAC Korea/618th Dental Company). This mostly means there is an annual field training, a requirement to annually qualify on M9 and some other M-TOE stuff. Doesn't make a whole lot of difference in the day to day, but some times its annoying. Field training is not fun, just feels like a waste of time in order to sign off on annual training reqs. But you know, army
-army in Korea has a standing 2am curfew
-every once in a while Kim up north gets an itchy trigger finger and we go on lock down. no pass/leave etc
-netflix just got better at blocking VPNs and the selection on Korean netflix blows.
If you have any questions, feel free to ask. I'll be here for a few more months before I head back to the states for residency.