Çınar's place was exactly as described. It's a spacious, well decorated apartment with everything you need for a short stay. The location is very convenient, safe, very close to public transport (tram, ferry and metro), countless catteries and shops. Çınar himself is a very kind and responsive host. He met us at a cafe during check in as the taxi driver did not want to drop us by the apartment. He provided extra linens, pillows and toilet paper per our request. He even gave us a ride to the mall during our stay. He also called us a taxi when we left which picked us up at the apartment. Overall, I highly recommend Çınar's apartment if anyone is looking to stay in Beyoğlu.
As for the area and the surrounding, please understand that Beyoğlu is a hilly area and often has some steps or inclined roads. So if you are a person with mobility issues or simply do not enjoy climbing steps, this area in general may not be ideal for you. Also worth mentioning that due to the proximity to the many cafes, restaurants, local schools and the touristy Galata tower, this area is always lively to the point that some may find it to be noisy. You can experience this from Taksim metro stop all the way to Karakoy tram stop. That is just the general vibe in this area and if you are okay with that, then you will have a great time.