I see in this tread a lot of talk about how good MASSs are and how bad TASSs are.
I have driven Maruti cars for over a decade and have shifted to Tata Manza this Feb.
As far as the hype about ASS of Maruti and Tata, I would like to add my experience with both Maruti and Tata ASS.
Maruti ASS
My 1997 zen sprung a leak in the radiator and got it replaced in Bimal, whitefield, Bangalore. The next day I drove down to Chennai and after reaching Chennai while driving down Nungambakkam highroad I started getting strange metallic noise from the engine, lost power and saw the engine temperature gauge redlining. I stopped the car and made the mistake of offing the engine. Soon the whole lot of coolant just sprayed off under the car and caused a great scene. After the engine cooled of I filled up the radiator and the coolant tank with water and drove off. Later on when I took it to a service station to find out the cause, it was found that the inlet and outlet tubes to the coolant tank were interchanged. Luckily no damage to the engine.
I had cracked side rearview mirror in my 2004 zen and wanted to replace it at Service Masters in Chennai during a routine service. The service advisor told me that the whole assembly (internally adjustable type – and the mirror alone was not available) had to be replaced and that it would cost 1200 Rs. I told him to reconfirm and he came back and said that it was so. I told him not to replace it and go on with the service. When I went to collect the car, there was a delay. So I just walked around and found the spares store. I went there and casually asked the guy there if they have side rear view mirror for zen. He asked me if I wanted the full assembly or just the mirror. I was like shocked. I then called the service advisor to the spares stores and then he said he was sorry and fixed the mirror for 110 rs.
Again in Bimal, whitefield when I gave my zen for accident repairs to the hatch and rear bumper ( a tata sumo had banged into me) they replaced the bumper and did tinkering to the hatch (it was only a minor dent). They delivered the car late in the evening and everything looked fine. The next day in the morning when I looked closely I found a small bulge where they have done the tinkering. Took the car back to them escalated the issue to the workshop/bodyshop manager, then again, the same sorry sir, please leave the car and we will get it done again. This time they did a good job. But screwed up the hatch lock. The key just keeps turning loosely without any action. The driver side remote hatch open lever worked, so just left it at that.
At Samy’s MASS near Don Bosco, Egmore, Chennai. Wanted to rectify the screeching sound that came whenever I brake. The chief mechanic test drove the car with me and informed me that the front disc brake pads have to be replaced. I said ok, but I want to be there when while you repair my car. After a lot of arguing with and elderly person who was in charge of the place, I was allowed to be there. They changed both the front disc brake pads and took drive inside their workshop. The same screeching sound was there. After a dozen braking attempts with another mechanic standing near different wheels each time they found that it was the rear left wheel that was making the sound. They cleaned the drum with some emery sheet and that solved the problem. Now if I was not there they would have simply said that they changed the Front disc brake pads and charged me for that.
I have a few more stories about MASS like the one in Suraksha, Boomanahalli, when they replaced the dash for removing a dead rat, they forgot to connect the drainpipe from the AC cooling coil to the outlet. That resulted in flooding the passenger side when the AC was on.
Tata ASS
When I complained that the high beam was flashing lower than the low beam, they had no clue as to what to do. They told me that it was the design in Manza, there was no adjustment only for the high beam, upgrade to higher wattage bulb, etc. I send an email to Tata motors and within 2 days I was invited to the service station and the very same technicians who claimed that there were no adjustments for the high beam located the adjustment screws and raised the high beam. They even asked me to check it out for a week and if required come back for more adjustments.
Noise coming from the AC fresh air inlet damper – replaced in 2 hours
One of the switches in the driver side power window switch assembly not working – replaced in 1 hour.
My Conclusion
Maruti is no better than Tata in terms of quality of work done.
I also found the washing and cleaning of the cars of the same quality both in Maruti and Tata.
Maruti may have an advantage over Tata over better customer interaction and customer comfort/facility, like better lounge, coffee/tea, etc
In the end, it all depends on the relationship that you maintain with the service guys.