Rift herald is stronger than baron buff imo (not considering baron buff is for the whole team, on one person rift herald is much stronger than baron on one person, or so I think). I've got the buff, started pushing top and that minions get 40% attack speed can take you to the inhibitor in freaking no time. Towers take more damage now too. If you are let unattended rift herald is a Very Very strong. If you attack its eye I've seen 1162 true damage dealt to rift herald on top of the AA (does not take a long time to kill it at all), and it's not a horribly short time so you can back right after even though its a shorter time than baron. Ranged champs deal less damage to rift herald, so most top champions being melee actually helps. your minions don't get tankier, true, but they do more damage, even if you are being prevented from attacking it yourself the minions will get effective hits on a tower that doesn't regenerate, even more if you are against a champ without clean waveclear. Baron buff doesn't even make caster minions tankier either, and they're the ones that are gonna get the most hits on the turret. rift herald is definitely worthwhile. does not take a lot of time and it has huge rewards.