Hi Daniel 
I think the major differences to take into effect are how big are your orders going to be. Dtg is good for smaller runs up to the hundreds, and screen printing is better for larger runs. Space is also a issue. If you have a big space for screen equipment that would cover that, but if you have a small space then of course the dtg is going to cover that better. It really depends on your business plan and what type of orders you plan on doing. If you plan on doing a lot of large orders, screening would be the way to go. If you want the capablilty of doing small orders in the hundreds and down to the one offs and such then dtg would be a better fit. What you first need to do is figure out what type of business you want to be printing and go from there
hope this helps with a direction to research some 
I think the major differences to take into effect are how big are your orders going to be. Dtg is good for smaller runs up to the hundreds, and screen printing is better for larger runs. Space is also a issue. If you have a big space for screen equipment that would cover that, but if you have a small space then of course the dtg is going to cover that better. It really depends on your business plan and what type of orders you plan on doing. If you plan on doing a lot of large orders, screening would be the way to go. If you want the capablilty of doing small orders in the hundreds and down to the one offs and such then dtg would be a better fit. What you first need to do is figure out what type of business you want to be printing and go from there