I have tried Looi's Meng Tong (he no longer there though), HL Jabar, Perfection Motors Allan, and Racewerks.... To be honest, the best mechanic is still yourself if you know what ur doing... I do all the basic maintenance myself....
All the mechs that I've encounter have proven to be good at times and bad on some other occassions... They range from minor maintenance slip-ups like losing some of my fairing fasteners, putting back fasteners at the wrong place, forgetting to install back the water drain hose... A bit more major cock up is nv tighten my steering stem nut to the correct torque...
The things is, all the shops that I've gone to ain't cheap so I expect some kindof quality in place... I'm currently sticking to Racewerks cuz by far, their value for money has a slight edge over the rest and its nearer to where i'm staying. Norman, Sam and gang are very helpful and open to discussion on technical issues...
Ultimately, they (ALL Motordiam) are all trying to make a living and if they can earn more from you, who wouldn't. Do a bit of research on the maintenance you want to do then ask for quote before you commit.