There are advantages and disadvantages to both a MacBook Pro and iPad Pro, but when it comes to extreme performance, the MacBook Pro is a definitely a winner because it holds additional processing power. It's also portable like the iPad, but it's more powerful. If you don't want to carry chargers with you or want a simple way to enjoy iOS, then iPad Pro is the solution. Slternatively, use MacBook Pro, because it's powered by Mac OS X, which is a full operating system.
Both devices are good, but it depends on what type of business you have or what are the needs. A sales representative from Apple should give you additional details.