There are mainly three differences between MAX22501 and MAX3485.
1, Max communication data rate: 100Mbps @ MAX22501 vs 10Mbps @MAX3485.
2, Logical level: The MAX22500E features a flexible logic interface down to 1.6V, MAX3485 features 3.3V logic and interoperable with +5V logic.
3, Output drive capability. MAX22501E is designed for long cables, it have a larger drive capability.