高于 is more formal and written than 比...高. Use 高于 in reports, statistics, and formal writing. In speech, 比...高 is more natural.
usage
The opposite is 低于 (dīyú, lower than). Other similar patterns: 大于 (dàyú, greater than), 小于 (xiǎoyú, less than), 多于 (duōyú, more than), 少于 (shǎoyú, fewer than).
