I'm not sure what your circumstances are, but we applied about 2 1/2 years ago for our 175. We were looking on here and saw that it was taking people years to even get a case officer, so we decided to come out on a working holiday after being advised we could transfer our 175 application to a 457 once we got out here and found someone to sponser my husband. What we didn't realise was that since we were in the country, it pushed our 175 application to the front of the queue. We ended up being contacted by our case officer within 2 months of being here and once we had our police checks and medicals we were preapproved within the month. We just went to Bali (cause you have to be over seas for the final approval) and got our visa stamps. We have now had our permanent residency since last August.
We didn't use an agent, because we had been told by a few people on here and others that they would rip you off. We have actually had a family member trying to get his sorted over here and has cost him over $17,000 throughout this last year and they still managed to screw up his application. We went to see a few when we were still in the UK and they just gave us dodgey vibes, so be careful.