I would say half and half. This is my second year and the smart strings for me are awesome because of how I do my display; however in year 1 I would have never have understood that really to know. From a still learning and growing perspective I would really first think about where stuff is going in your display, what you are looking to do (effect, visual wise) and then map it out a bit.
First year did LE's and even SSRs and yep even a Freestyle. From that experience LE's are by far so much better in my display than all the rest for simplicity, troubleshooting, it is a lot more visually helpful when there are issues. Now from the display side of things what I found was and I'm basing this on a Halloween display that I did prior to the Christmas one because I was eager to jump in and get started seeing how things worked... From that perspective the LE's worked great; what needed thinking out was how I was using light sets. Sometimes I wanted to change from one color to another color in my display rather than running 1 set of lights I need two sets one of each color; two LE channels, etc. My pumpkin display has so many places that I only need like 10-50 lights of a specific color but need multiple colors to change the pumpkin faces; what seemed simple actually became a lot more complex because of the multitude of strings I was running to affect colors. Don't get me wrong it came out great and the LE's were true work horses but compare that to Smart Strings and for me in that situation it is awesome because now 1 small smart string of say 20 lights can replace 4 regular strings of 20 lights.. With SS I get basically whatever color I can think up; with the 4 regular strings I get 4 colors. I have so many uses for smaller sets that can be any color rather than multiples of sets of 1 color each to get the same effect; SS looks like it will be amazing for what I am doing.
Now like previously posted larger megatrees are going to be expensive in SS; so it really comes down to understanding your display. Your first year I think the LE's are a great hands on start and great learning experience. After the first year it will give you so many more ideas and you'll have a much better understanding of what works best and what equipment fits that need the best. So I would say either way you go you're in good shape. Start with LE and then move up to SS if what you are doing works well with such and is cost effective for your display.
-Mike