The injection molds will allow you to make baits that rival most others off the shelf giving you the ability to have nice appendages with great action.
For me, there is something to be said about hand pouring. It is a great way to really "get to know" the plastic and how it acts.
To get a good feel for the plastic is to know what happens when adding salt, softner, hardner... and so on.
I feel I have learned that by spending countless hours sitting over a pan and a hot plate.
Hand pouring also allows you to get started at a lower price point if you happen to be on a budget.
For most of us that have been doing this for a long time, hand pouring was more or less or "right of passage" that progressed us into what we do today.
But... I also agree with DeBehr.
If the injectors were available eight years ago when I started making my own soft plastics, I would have went straight to them, I just feel that it may have taken me longer to
gain the experience I have developed over the years.
Good luck!