Do you need RF? If so then there's your choice. If not, then I don't see the point in spending the extra money for it.
I have a Harmony 720 (6 soft buttons vs 8 I believe on the One, probably some other differences as well) and a Dinovo Edge keyboard. I use the 720 exclusively for movie / TV watching, only grab the Edge when I'm doing more computer centric tasks (updates, forum reading / responding, etc). While I've never used the Mini, I don't believe it can control other equipment? Perhaps with a IR blaster and EventGhost or some other IR software you could get it to work, but you'd likely have to program every command, whereas the One has virtually everything already preprogrammed via download.
So, I'd recommend the One (or an older model via Ebay if you don't need to control as many devices as the One offers) or the RF version if you require RF.