Well everyone speaks out from their experience and perspective. When I decided to go for it, I was baffled about getting an agent but then I spent a day or two on browsing immigration websites and related forums etc. I understood everything and decided to take one step at a time. First, I applied for the Skills Assessment once, I got the results, I started with the English test and once I was through that, I lodged my EOI. Got my EOI, then, applied for the PR.
Whenever I had a doubt, I posted it here on the forum and people are so great up here, they answered my queries and helped me to get through. This way, I did everything own my own and I am glad I did as otherwise, I would have had to shed about $1800 on an agent which I saved. YIPPEEE!!
So my suggestion is, unless your application is complicated by any means, do it yourself!