After nearly 2 years of bombing (September 2014-June 2016), the US-led coalition (14 countries including Saudi Arabia, Turkey, Jordan, and a few other Muslim countries) has killed under 500 civilians in Syria.
Russia (that's one country, though fairly big), in less than a year (September 2015-June 2016), killed nearly 2500 civilians in Syria.
Civilian casualties by ISIS are difficult to estimate, but they are definitely in the thousands.
This article from a year ago states they executed nearly 1800 civilians in a year, and with mass graves being found near the cities captured by ISIS, the number is much higher.
These numbers are all from the Syrian Observatory for Human Rights.
If you said Russia was as bad as ISIS, then just looking at the killcount I would say yes. But the US-led coalition? Not really.
That might sound awful, but at the same time, not bombing the region brings its own risks with it. People would feel abandoned and as if their lives really don't matter to the west, which in turn creates a lot more hatred. ISIS would use that hatred to grow their numbers, to turn the people they oppressed into people that will fight and die for them, and that's something we want to prevent. So we choose to bomb, and in these bombings there are sadly going to be civilian casualties, but fewer casualties than there would be if we stopped bombing. It's literally choosing the lesser of two evils.
Definite numbers of casualties and injured are now known. 84 dead including 10 children and teenagers, 202 injured of which 52 critically.