Everything seems to be about holiday lights now, with new LED light strings using a fraction of the usual energy, with almost no fire risk if installed correctly.
Do I recommend them? Yes and no. Depends on colour.
Coloured – yes! No reason whatsoever not to switch to LED.
Cool-white – no. For the holidays you want to create a warm fuzzy feel, right? Using chilly ice-blue LEDs is not the way to do it. *brrrr*
Warm-white – maybe. It depends on how keen you are on getting an exact incandescent replacement. If you are, there aren’t any. What is sold as “warm-white” tends to be either pink-white, yellow-white or greenish-yellow. How much they’re off from the brilliant golden-white of incandescent lights varies between models and brands. Some are close enough to be acceptable. Make sure to look and compare before you buy.
Maybe you don’t care as long as there is light? Then by all means, do buy them! Being left on perhaps all night and even all day for a whole month or two, it can be well worth the investment. Just get ones that look good enough for your standards.
Here are some tips from Gadget Guy on how to calculate savings: What Holiday Lights Are Best?