I had a paid stay at the Westin Chosun Busan for two nights as a PPE (soon to be Tit).
This is a very nice property that sits out facing Haeundae beach on one side, and a park on the other.

Upon check-in, I was recognized as a Platinum member and informed that I received an upgrade to an executive suite with a beach view. This was not something I asked for (either via SNA or just asking), so it was a very nice surprise. Upon entering the room, the TV was set to a message with a personalized note, and the bed had a small gift bag with two fortune cookies.

When the front desk was explaining lounge access to me, they informed me that I was invited to have breakfast in the restaurant, which was a nice surprise as well.

The lounge is a dedicated space on the 2nd floor (I guess no longer top floor it seems?), that has really terrible food for the evening happy hour.
The guacamole was very watery and looked like a sickly pale green. Like a mix of ranch and mashed avocado. It tasted how it looked. The salsa they had were clearly a jarred salsa like a tostitos wannabe brand or something.
No crackers or bread to go along with the cheeses/cured meats that were available.
They had two hot food choices each night. The first night was bacon-wrapped sausage and chopped steak. The second night was bbq wings and a sauteed shrimp dish I don't remember the name of. Despite how it may sound, the offerings were pretty bad as far as taste goes.
There was also a selection of fruits, which was the best stuff they had out for the evenings besides the booze.
Regarding the booze they had a variety of liquors, though nothing special. They had Jack Daniel's, Ballantine 12-year, Absolut, etc. For beer they had Cass and Budweiser. Of course there was a selection of different wines.
An interesting offering was that they had canned gatorade available, so that was kind of nice.

Breakfast in the restaurant was really good. Lots of variety, the french toast I especially enjoyed. They had Chinese, Japanese, Western, and Korean-style breakfasts
They also do offer breakfast in the lounge, which is still a pretty decent breakfast. Scrambled eggs and bacon, in addition to cereals, fruits, and breads.

I thought it was kind of funny that they had an Irish pub on-site called "O'Kim's". I had to explain to my wife (a native Korean), why I thought it was so funny.

Sauna/gym access was included in my stay, and it is very nice. Like other high-end gyms in Korea, everything is included. That means workout clothes, temp-use headphones, the hot tubs, the saunas/steam rooms, full showers, etc.

As said, the location is between a beach and a park, so beach access is available just by walking out the door. There is a cool setup of "pojang-machas" (tent-based restaurants) along the beach, and close access to a Busan City Bus Tour stop. You do have to walk a bit to get to convenience stores, but they're still close. Lots of hotels in the area along the beach, so expect to see travelers if you're exploring. The view from the room is pretty nice. Reminded me of the view I had at the Fountainebleau in Miami.

I was here during the Lunar New Year, and the beach was not too crowded, but I heard it was much more people than they usually have. Apparently in the summer the beach gets crazy crowded, so just FYI.

Anyway, if anyone has additional questions, feel free to ask and I'll do my best to answer.