Cat6 cables, also called Category 6 or Cat 6 cables, provide lower crosstalk, a higher signal-to-noise ratio, and are suitable for 10GBASE-T (10-Gigabit Ethernet), while Cat5e cables support only up to 1000BASE-T (Gigabit Ethernet).
As a means of future-proofing your network, Cat6 is generally a better choice and worth the small premium in price. Cat5e and Cat6 cables are both backwards compatible, which means newer Cat6 cables can be used with older Cat5e, Cat5 and even Cat3 equipment.