Well, is LED lights better than flash...the answer isn't that simple, so here's some pros and cons for you to make the easiest decision. Pros: Controlled light, it is SO easy to see your final shot, after all with LED lights, what you see is what you get. Even when you gel them, you see that colour, move the light where you want it and you get the perfect shot every time. Plug-em-In, yes, if you in a studio or near a plug, you can probably plug them in...that means no worrying about flat batteries or recycle time.
Cons: Slow shutter or High ISO, a flash helps freeze your subject, even in a low lit situation you always get sharp images, thats because a flash pulses so fast it freezes that image on your sensor, with LED lights, you have to either use a slow shutter or higher ISO. They not that bright, relating to the above Con, LED lights aren't that bright, I know when you look into them you feel blinded, but thats the effect of an LED. A flash can be pointed to the ceiling and light up and entire room, an LED...not so much! Battery power, flashes don't use much battery between shots at all, almost nothing. Ive left my flash in my bag on and the next day it has power, LED lights unfortunately use a lot of batteries as they always on. They large, yeah, to get some decent amount of light out of them, you need a large LED light...they take up a lot of bag space...so great for a studio, perhaps not so much for location. They blind you, when I said they not that bright, it's true, the light doesn't travel like a flash, but when they on pointed at your subject, they insanely bright, chances are, your model might need a pair of sunglasses. So it may seem their are far more cons than Pros to an LED light...and its the reality of it...however, the 1 Pro that is awesome is that your light is controlled, shooting flash for inexperienced photographers can almost feel like a 'shot in the dark' no pun intended. I hope this helps, any questions, drop them in the comments below.