Butter wax is a great wet look wax, however durability isn't very good. I personally think of it as a show wax, and looks good on any colour.
Really depends on what you want from a wax, max bling look, durability or a bit of each.
Of the Chemical Guy's products I'd say the XXX hardcore for reasonably good looks and 2 month durability, 50/50 for bling looks for a week or so, then it tones down a little but lasts 2-3 months (still looks good but not quite as good as first week). Max bling has to be the butter wet wax, but durability is measured in days in summer and hours in wet/winter.
From here it also depends on what sort of price you want to pay for a wax, some of the high end waxes (Zymol or Swissol) will give the max look with great durability, however these do require their own cleaning/cleanse products before to ensure the best possible results.
Finally the end result is only as good as the preperation, even on Rage paints.