P.H. Yoo Panama is a well known condominium building with short term rentals. It has 2 towers of well sized apartments and excellent facilities including awesome restaurants, right on on Avenida Balboa. Some owners are full time residents and others rent them on yoorentals.com and apps like AirBnB and Hotels.com. Each is unique so they will not look exactly like the one we rented. We were pleasantly surprised many times exploring the building and enjoying the huge pool area. The building and the people working in it are great and it gives you a really good feel for Panama City.
https://yoorentals.com/
Map location: https://www.google.com/maps/place/P.H.+Yoo+Panama/@8.9760388,-79.5261745,17z/data=!3m1!4b1!4m6!3m5!1s0x8faca8e705d48aff:0x1fc0b2004b1b2f9d!8m2!3d8.9760335!4d-79.5235942!16s%2Fg%2F1q2w1flbh?entry=ttu&g_ep=EgoyMDI1MDMxNi4wIKXMDSoASAFQAw%3D%3D