We've had Indigos for 10 years, and no, we generally don't use PlanetPress to print to them.
It's not due to a fault with PP. The various HP rips are very slow when processing multipage files, either .ps or .pdf; if you can live with the Indigo processing time, then PP works just fine. .ps files rip a little faster than .pdf. 100 pages will rip in more or less a respectable time, 1000 pages will take a few hours, even if simple text only pages. If your particular HP rip will process VPS, you could try that way. Our current main Indigo rip is not VPS enabled, we have an older off-line rip that is, and VPS works on that, but still dead slow.
Processing time seems worse because Indigos are not rip and run, the press can't start printing until it has a complete file. What you must do is break up your data into chunks and rip in sections. Then the press can be printing one section while more sections rip. However, the press can print far faster than it can rip the next .ps file, and depending on the particular Indigo, you really don't want to overfill the print queue.
We do have some jobs we do on a regular basis (usually <100 records at a time) that run as a PPServer process. We drop the data in a server hot folder, Server loads the PP document, and outputs .ps directly to an Indigo hot folder that has a specific multi-up imposition. Works well.
As to colour, PlanetPress passes through whatever colour and resolution is contained in the placed files of the document, so that's not an issue. For the colour of any PP object like type, you'll have to experiment a bit with CMYK mixes, since PP doesn't have Pantone libraries. You also will have to deal with imposing any multi-up jobs. I would say use the Indigo software for that, it is a clever piece of work, as you will find.
Play around and see if PP sent to the Indigo will do what you need. It probably will, it just won't do it fast enough.