If you want to get accepted by an literary agent then it is very difficult and many things will come into consideration besides the quality of your book - for instance, budget, publishers preferring more established authors because they are more likely to sell,etc. Having said that, I believe it is definitely worth trying if having a book published is your goal. After all, if you don't try you'll never know. And if your writing stands out above all others, then you are in with a chance and you just have to keep trying, even in the face of (a lot of) rejection. Just don't give up your day job just yet!
Of course, you can publish your own book, but personally I would not do that - I know there are people here who have though.