Ups: Reduced maintenance, additional stability, ease of adjustment, and relatively low long term cost (aragonite media and CO2 are cheap).
Downs: Outrageous initial cost. A full setup is about three times worse than you think it could ever be.
Edited so I don't get lynched: You might want to look into automated two-part dosing as well as an alternative to meeting Calcium and Alkalinity demands. It's a bit more simple to use, costs a bit less initially, and has all the same benefits. It's all a matter of preference.