Pressure rating, maximum differential pressure (opening and closing), power supply / air pressure required, instrument connections, factor of safety on stem / actuator - basically anything you managed to write on the data sheet ( you do have a data sheet don't you??)

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

May ask for the references where the new vendor sold the MOVs to.
Also, plan for a shop inspection and SAT for the MOV before shipping.

Full stroke timing? fails in-what-state on power loss? Manual override switch? Right control signal? Right motor drive voltage ? Position feedback? Position indication? Is there a wiring diagram pasted on the inside of the actuator cover or do you have to beg one from the vendor? (a major electric actuator vendor keeps their wiring diagrams very close to their chest), auxiliary position switches?

Cv? Body, flange size/material? Trim material and characterization the same? Will the assembly fit in the same space? Paint match your plant color scheme?

Well, it depends on the application. Why are you replacing the old valve with one from a different vendor? is this a Motor Operated Valve or a Multi-Orifice Valve?