I honestly find a conversion to RGB more compelling than just a conversion to LED (full wave, single color).
By the way, are these RGB LED pixels all what we would call "full wave", or do they vary?
I think converting the megatree to RGB is enticing, but not only is the cost fairly high (just like with LED), but
your taking a technology leap (strands require waterproofing?, DMX or Pixelnet, Controllers, Hubs, and software to handle 1000's of channels in RGB).
So I think in the interim, you can get your feet wet by doing less ambitious projects in RGB, vs. going 'all in' in the first or second year.
I also think that it would be highly compelling to convert from say C9(s) on the house [ I do 3 colors, or 18 strings per house ] ... to a single set of RGB strings ... and then be able (a) install one string (vs. 3)., (b) save lots of power., (c) get some AC channels back (for me, I'd save 9 per home)., and (d) use more colors and do cool RGB chases, etc. What I don't know is how do they compare, meaning, who would a set of RGB smart strings look as compared to having 3 sets of C9s on the roof ... and obviously those are quite bright. And how easy it it to hangle RGB strings straight and durability, etc.
So I think I'll be doing things in phases, and probably ending up with a RGB megatree last.