samchi媽,
Both are in Patong area.
Millennium is the newest one in Patong. It has a mega shopping plaza w/ Carrefour over there. But it is far away from the beach, around 10-15 mins walk.
Holiday Inn is more closer to Beach, around 5-10 mins walk, but comparatively older.
Honestly, most of the hotels in Patong are “city” feel as Bangkoks’. The space and size are not bigger than w/ private beach.