Vaporisers are vastly different between singlepoint and multipoint systems, so you need to know what sort you have to start with.
Multipoint vaporisers are high pressure and not all are the same pressure, so you'd need to find out operating pressure as well as bhp to check equivalance. Multipoint vaps often have a temperature sensor which may or may not be compatible.
Singlepoint vaps are functionally pretty much freely interchangeable within the bhp capability, except that the plumbing may not line up; adaptors, hose changes, pipe extensions etc. may be needed to fit.
As already mentioned, some have a built in shutoff solenoid. If you replace with a different brand, you may need to add an external shutoff as well.
Replacing with same brand/model is usually going to be much easier.
Whatever you do, it WILL need setting up properly afterwards, do not expect to part-swap and drive away.