Yes, flowering will take a little longer however if you're using the right led lights your nuggets will be way frostier (IMO) compared to HID nugs. I've also noticed that pistils were much more elongated with LEDs. I've only done one run with Leds, and that run was somewhat basterdized by my travel for work, vacation, and me not locking my grow room and having a 3 year old helper pour nutes everywhere on my plants - anyway - the point is I grew two strains I've also grown under HID. The flowering took a bit longer, the plants seemed to require less nutes, and when I reach for Mason jar of either strain I find myself reaching for the led grown nugs first. Also in the interest of full disclosure harvests under LED (this being my first run) were about 10% less than what I usually pull from HID. There is a learning curve here as well and it took me a while to figure out how to pull upwards of two oz off an auto under HID. I suspect once I gain more experience with my new lights I'll be able to take it close to, if not equal to the harvest figures with better quality nuggets than HID lights.