To be honest, from a machine knitting perspective there's not much difference between how the two techniques are performed, as both result in floats.
That said, machine knit "jacquard" fabrics done on a flatbed machine without a ribber attachment are technically fair isle but tend to look much more alike on both the front and back sides than a standard fair isle pattern, but have a much shorter float on the purl side than fair isles.
Jacquards done with a ribbing attachment have the floats hidden inside, and are technically knit in the round on the machine, and these fabrics are truly reversible.
If you're interested in doing either on a machine: It's much less labor intensive to work these fabrics on an electronic V bed machine like a Passap than on the standard punchcard/electronic portable flatbeds with a ribber attachment. Though IMO, that takes most of the fun out of it.