I was going through this amazing post here at TGO which talks of trekking solo. As far as I know of TGO culture, this question here might sound a really opinion-based question, or rather a too broad kind to have a concrete answer, but I would rather take up a chance to post it outright.
I have trekked solo a hundred times, and I do have had close shaves on a rare occasions where a single mistake could put me in deep trouble. Having said this, I also have had times in wilderness, so good and close that I would never be able to have such when within a group. And, regularly, when I get back home, people who are really concerned, ask me if its really worth going alone, and I realize that I should have a line drawn in mind that decides on which side I am, to go or not to go.
I believe a little work with Pros and Cons over this point can really bring about factors in deciding whether to go solo or not. On a safer side, a rookie hiker/trekker would certainly pick the things he/she might need to consider when deciding upon the same.