If you apply through 175 .. you would fall into priority 4 category as your occupation is listed in SOL and if applied 176 (after getting sponsorship) , you would be in priority 3.
Now the estimated time for processing of visa according to the following site :-
Client Service Charter
is 18 months for Priority 4 and 24 months for priority 3 ( High risk NON ETA countries like India)
Now , everybody in the forum is going towards 176 as it seems to be approved soon, but it has to be clearly understood , that with 176 , one has a restriction on work permit.
If you are sure that , you would be getting a job in NSW or VIC and would be settling in these states... you should be going ahead with 176 or I feel 175 is the best .. though it takes time .. but worth the wait .. I guess.
Regards
Mansin