You are right to question it as I live in the ghetto of ZhongHo, right near a taishichang(whole lot of thai writing and indonesian). I’m about 15 minutes from the MRT and I live on the first floor. I had to go to a lot of places to find my decent place and it was absolutely filthy when I got it. It took me about a week to make it livable and a month to actually not be embarrassed by the dirt and grit(most of which has now been cleaned away).
If you go with TMM, expect to see 1 good place out of 5-10. I would also suggest going to the apartment you want at different times and making sure that there are no large temples near it. You need to make sure that the area is livable. You will never get any sleep if on a main road leading to a taishichang and no late mornings as you will be woken up by the yelling of the vendors. Never be in a rush to get a place and always check out the circuit breaker. I saw a 3 bedroom wired for 4 AC’s and a washer with a 30amp main breaker. You have 3 people running everything and you get to see all the lights go out real quick. My current place was a Changfang and is wired with a 100amp main breaker. I could run a small factory there if I wanted with rooms for foreign laborers to sleep in.
You should agree to move in a week or so after you pay the deposit and get the keys. Older places will need a thorough cleaning, especially if the family that use to live there is the family renting to you. They will often give you the keys when you pay the deposit even though the move in date is 1-3 weeks away. I use this time to move small things on my scooter and to get the place cleaned up. I had to install an oven exhaust fan and exhaust piping, gas line to the stove from the tank, a RO water filter, fix the toilet seat, mop the floors 2-3 times. Most things are negotiable and be sure to negotiate all of them before you sign the contract and give a deposit. Things to check on are gas bottles, hot water heater(mone was broken landlord replaced it before move in), windows, stove, toilet, shower, leaks from upstairs.