They've been around for a few years now, 727 Charter pax ops, used to see them down in MIA a lot.
When I went for my Transmeridian interview a few weeks ago, there was a Planet 727 Captain in there with me who basically said he was hating his QOL (or lack thereof). "Interesting" is putting it nicely I believe, as he told me to run far, far away from Planet unless it was a choice between there and wearing that orange apron at Home Depot...
You might have better luck, it really depends what your background is. If you've flown part 135 freight, it might be an improvement. If you haven't flown for a Supplemental 121 op before, then you're in for an "interesting" ride...