If the old one clogged frequently it could have been for several reasons, and one of them was a poorly designed toilet. But, if you have a drain problem, no toilet will work properly until that is fixed.
When the thing was installed, if you needed two wax rings to set it, one of them may have shifted and partially blocked the drain. If the drain is an offset drain, some designs are lousy, and can cause blockages. No toilet can handle huge gobs of toilet paper I've seen some people use. I don't get it where they think they need like half a roll to wipe their behind. Any dumping of femine products can mess up any toilet, too.