I started using TaxiforSure service 2 years back when a family member suggested it. I have used their service in Pune mostly.
Earlier it was good but after OLA acquired it it has gone nuts.The best aspect is the pricing which is always cheaper than all other services. I think in India people always take cheaper services and quality awareness is less. That is why people do not take Meru cabs - which has best in class taxis and drivers - that much as they take OLA and TFS.
TFS cars are worst in the market I have seen. Rugged, old pathetic cars driven by worst behaving drivers.