Thought about a DTG Printer a while back. After a long time researching and speaking with various businesses that had them and sales reps selling them our decision was not to go that route. Our reasons were such:
1) Unless you run the printer daily the cost would outweigh the sales. We figured that to pay for it we would like to have done 30 to 45 shirts/items a day.
2) At the time white ink was the latest and greatest but the downfall then and still now is that the ink is made with titanium dioxide that has a bad habit of settling out of solution not only in the ink tanks but in the delivery lines and the print head. Unless you perform a head cleaning, line cleaning each time you close up shop you set yourself up for a clogged print head. This can run anywhere from running a clean cycle to a print head replacement that can run upwards of $400 on up. Cleaning solution also runs up your costs and it is required to clean your lines and print heads.
3) With the cost of setting up a DTG Printer, ink supplies, cleaning solvents, time, cost of the printer itself and a quality heat press we decided that screen printing was much more in line with our budget. Heck the GT-541 itself was $24,000 plus shipping and setup charges. That will get you a premier screen print setup.
4) DTG Printing is not designed for high volume runs, ink costs compared to screen printing are very high and time per shirt/item is much higher.
DTG Printing has a valuable market but doesn't replace or compare with screen printing for volume. Screen printing likewise cannot compare to the detail obtainable with DTG Printing.
Hope this helps your knowledge base in your decision. Check out the web, ask around.