Let me shed some light, I sell DTG and DTF printers
MOST IMPORTANT, and I'll discuss this later: POLYESTER cannot be done on DTG effectively, with DTF, yes!
1. Cost per print / I have strong knowledge of Brother and Kornit. Kornit printers use approx 65 cents to $1.25 depending on the model of printer; ALL other printers, Brother, Epson, et al, their cost per print is anywhere 2-5x more in ink and pretreatment
DTF, the cost per square meter (approx 12 shirt fronts) is LESS THAN $3 - or approx 33 cents per shirt!!!
2. Maintenance: all use water based inks, so you have to clean