LED all the way. Just don't get them at walmart. This is one thing you gotta head over to the home improvement stores.
In my experience you get better quality for about the same price. Plus they usually have some good deals.
We got LED lights from both Home Depot and Lowes last year and promptly return them. We all agreed that they looked like crap because they give off a bright white/blue color and look poor. You just can't beat the nice warm yellow glow of regular christmas lights.
LED if the color looks ok to you. For one, you have less to worry about when stringing multiple lengths together. They use so little power that you just need fewer outlets.
The 3 set rule predated LEDs but companies were forced to keep the warning on the package until last year I think. You can put about 20 strings end to end just fine.Some LED strings will say to only use 3 sets max, so you have to make sure you get some that allow for more if you want to make long runs. I asked about what happens if you use more then 3 on those types and the person told me they start to get dimmer. Pretty much getting commercial ones avoids this issue, or just check the maximum connections on the box.
The 3 set rule predated LEDs but companies were forced to keep the warning on the package until last year I think. You can put about 20 strings end to end just fine.
Here's the deal about Christmas lights. I put about 30,000 of them on my house every year, so I know what I'm talking about.
LEDs by themselves last an incredibly long time. The problem is that most LED strings are very poorly made. They usually don't get the correct voltage and over driving them can burn them out in a few seasons. Almost all that you find in stores lack full wave rectifiers so there is a very annoying 60 Hz flicker. The colors can be very brilliant like the blues, but white is very harsh since it's really blue with a tinge of yellow. There are warm white strings but even they cannot match incandescent clear strings.
However, the absolute biggest problem is that they rust. If the LEDs are not sealed, they will rust and can in just a few weeks outside. The LED leads are made of metal that rusts and eventually will corrode. Do not buy any LED strands with replaceable bulbs. I've had good luck with sealed LED strands but most of the LED replaceable strands lose a couple LEDs a year to rust.
Also, a 100 count string of incandescent can be as cheap as $2-3. The lowest you'll find a 100 count LED string is around $12-15. Usually 50 count strings go for $10. If you buy cheap LED strings, they won't last much longer than an incandescent string and will not make up the difference in price by energy savings.
I love the look of the LED colors but you're going to have to spend $20 a string to get something of quality that will last a while.
Until you spend an entire day every year going through strings replacing one bulb at a time trying to find the infamous one that is defective because 1/2, 1/3, or 1/4 of the string will not light you will never truly appreciate LEDs.
