But if it's that great, why did it fade away?
Well, for some unknown reason, around the 9th century, the usage of whole sign house disappeared and was replaced by Placidus. Don't take my word for it, you can listen to a podcast on this topic by Chris Brennan or read a relevant post from DarkStar Astrology. Some may say if Placidus is no good, then it wouldn't have been around for so long thereafter, but one of the reasons its popularity was due to the availability of the tables used by astrologers in their chart calculation. Imagine people looking back on us in a hundred years time and wondered why Microsoft was being used so prolifically - is it because it's the best?
For those of you who use Astro.com, over 20 house systems are available for users to choose from when drawing charts. Astrologers from all over the world have their own preferences, so it's a matter of personal choice.
I still use Regiomontanus for horary (as it was used by William Lilly), though I convert it to whole sign in my head to get a different perspective (if any).