I have used several varieties of LEDs outside for a couple of seasons now.
My largest are the C-6/7 size. They are bright and intense...especially if you have a single color string.
I had one issue with mine last year, the GE brand has plastic covers that snap over a short, flat, replaceable LED light. While having the option to replace burnt out -or damaged- bulbs, the covers popped off toward the end of the season (maybe it was the squirrels that took them off?). I had to dig around the base of the bush, collect them, then put them back on. This little hiccup was not a problem with the solid red LEDs I purchased from Kirkland/Costco..but those bulbs aren't replaceable.
They are great otherwise, but expensive, so watch for end of season sales when adding to your collection.