The production values and budget in BBC are much higher, they've covered more snooker than anyone else and have a consistent funding, where-as ITV rely on advertising, they've only previously covered 1 or 2 tournaments a year and never the biggys.
Apart from that their coverage is just as good.
I'd say that from a commentary and analysis standpoint, ITV4 is way superior. Phil Yates is a bit of a idiot, and though Jill Douglas seems nice, she isn't as polished a present as Hazel. But I still prefer ITV 4's coverage from a commentary / analysis standpoint to the BBC. During The Masters final, I had the second session on Eurosport, I just couldn't take the BBC any more.
The BBC is more polished, and more professional looking. (And doesn't have adverts all the time.) Somehow they make it look like a bigger occasion when they're on the screen. If only they could find some pundits who care about snooker as much as they care about golf and perving Selby's wife, we'd be on to a winner.