Thank you all for your replies!
To provide one more opinion piece on BCH, I would like to add my personal experience now after having had the checkup yesterday. Maybe someone will stumble across this thread in search of information in the months ahead.
So I went yesterday morning for the "Platinum checkup". I arrived at around 07.30 and headed to the registration counter as it was my first ever visit to this place. Registration went smoothly and took less than 5 minutes. From there it was straight to the heath checkup area on the second floor, where a nurse was immediately available to check me in. During this quick process, I was also allowed to choose a doctor from a list of around 10 or so with whom I would like to discuss my results later on.
It was easy to communicate with both doctors and nurses in English. Whilst the building has at times more the flair of a government hospital (compared to the so-called "5* hospitals like BNH etc) I was impressed with the efficiency and speed at which the whole check-up was conducted. Took less than 3 hours for the original checkup booked. It was nice that at all times a member of the staff would take you from one department/room to the next, always doing the communication with the department staff informing them on what I was there for etc. Easy going, and actually better than my one-time experience at Samitivej where I was only given directions on where to go next etc. including changing building complexes etc. So a big thumbs up from me for BCH.
Once all test results were in (I headed back to the department at 10:30 after using the food voucher in the food court) the doctor spent a lot of time explaining and discussing the results. I was very happy with that!
Given that I only paid a fraction of the price BNH & Co would have asked for, I will definitely visit BCH again for future tests.
On a side note, given one specific test result and a family history of issues with that one, it was suggested to me to see an Endocrinologist about it. I accepted and was seen by one 90 minutes later. Due to a pre-existing condition, I also asked for an appointment with a spine specialist, who I was also able to see within minutes after reviewing the general test results. So, yes, very happy with the doctors and the overall experience/process.