I've recently been noticing a strong trend in the games I play.  That trend is that generals that buy monks or other priest idol minions do really well compared to those who don't.  Even late in the game, the priest minions heal a very large amount of health over even a fairly short battle (a 10 second battle, they can often heal you twice, for 20 to 40% of your health total).

In fact, the most one sided games I've played involved 3 monked up generals fighting three assassins.  Snipe doesn't do greater dps than a priest heals, same with low level spit.

So, thinking about this recently, and playing a Sedna build, I actually bought counter healing when facing a pair of enemy healers... and then I started doing the math in my head.

In 1v1, my opponent had about 4k health.  We fought long enough for me to do two level 3 pounces, so that's like 8 or more seconds.  During that time, the opponents monks would have healed twice for 400 hit points each.  By picking up this skill I got the equivalent of an extra pounce in, for the cost of no mana.

The more opponents with priests around, the more I started to notice just how much faster they were dying, it was miraculous.

In short, I think Monks et al are incredibly strong, and I think that makes counter healing a skill that is much much better than it looks.