Anyone have much experience with either of theses, With V.F.D.s

Generally used to reduce upstream harmonics.

I used to deal with them quite a bit but I'm rusty.

Go here:
http://literature.rockwellautomation.com/idc/groups/literature/documents/td/1321-td001_-en-p.pdf

Good information at the manufacturer's sites TCI and MTE .

Except for public school jobs where the engineers don't know any better, I almost never see them on the front end of current generation VFDs. I don't know of a single industry in this area that routinely installs them as a preventative measure without doing a power quality study first.

Load reactors are still common, though.