LED for marijuana growing

A question from a fellow grower:

I was wondering what you thought of LED lighting and if there was any in particular you would recommend? Also, what is an E27 fitting and how easy is it to use with the LED?

I am hoping that one of our members can answer your question. I personally only answer questions that I have personal experience with. My opinion on LED’s. Too expensive vs HID. HID much for efficient for the $$$

Enhanced fluorescent, CFL, or small MH for seedlings, clones, moms
Large HID for beg, and flower. IMO