What's the difference? The primary difference is that the pro-dies have a dedicated die piece for the female vs male snap piece, which need to be switched out depending on which side of the snap you're installing. The no-change dies do not require switching dies.
Important! Professional-grade dies are available only for the KAM heavy duty table presses. They do not fit the portable KX pro-handheld or mini-table press.
Most (not all) people who have used both versions seem to prefer the no-change dies. However, technically speaking, the professional-grade dies offer the utmost precision.