My bad experience has been with Defense motors and Toyota Eastern.
With Defense motors,(since i bought my car from there, i went there first) i felt that when i got my Altis back, they were very rough with it. I kept seeing new marks around the interior door handle, and dents on the corner of the console which i didn't see earlier but found out later.
Also below the driver seat, there is the railing where the car seat position can be adjusted(forward or back), that railing has a plastic cover (i guess for dust protection), when i got my car back from maintenance the plastic cover was broken and with a poor attempt to hide it under the back floor matt. I mean essentially it isn't a requirement for driving but my car was brand new, hardly 6 months and you would like to keep it in pristine condition. These small experiences gave me a bad impression that is why i thought i switch to another.
Sadly i switched to Toyota Eastern. I only got my car maintained once at 15,000 KM but when I got my car back i felt apart from being cleaned internally they hadn't done any maintenance, i was told that the oil was changed but they never gave me the oil box, and the over feel of the car was same as when i gave it(i felt as if they didn't tune the car either). So now again i am looking to go to another dealership for maintenance.
After reading this chain, i am thinking of trying Toyota Southern since, i guess since it is located outside the city they don't see as much customer flow as the dealership inside the city, therefore hopefully they would be more customer sensitive then then main ones like Eastern or Defense.