(edit: I'm only talking about the bridge pickups in this post.)
Really depends on what you're going for. In my mind, the Pegasus and the Illuminator are two very different pickups. The Pegasus is pretty warm overall and scooped sounding. Lots of lows, lots of highs, but a little lacking in the midrange. The Illuminator on the other hand, is very punchy in the midrange but doesn't have the same low end of the Pegasus, or the top end shimmer. It's an Alnico V vs. a Ceramic, so there are a lot of subtle tone differences there. The Pegasus' sound is sort of spread wide, with the fat bottom end and sparkly highs standing out above all. Whereas the Illuminator is more of a tight and focused sound. I'd wager it has a pretty balanced EQ, contrasting to the Pegasus' scooped EQ. Both are a little rolled back output-wise, and that helps with the versatility of each.
I recently bought and returned a Pegasus. I was sold on what I read about it, but after playing around with it, it turned out to be something else than what I had in mind (my fault, as a consumer). I'm working on a project with a buddy, so the main focus is recording, not really any live playing, and I just wasn't liking how it fit into our mixes*. Wasn't cutting through how I wanted without the midrange. I will say that it sounds good as a bedroom jamming pickup though, and the clean sounds are very pleasing to the ear, however I wasn't really getting the whole "enhanced string separation" thing that's advertised with the pickup (I found that the strong bass could easily swallow up and blend everything together on big chords across all the strings). My friend has an Illuminator in one of his guitars, so that's mainly where I'm drawing these comparisons (so you know, full disclosure, take it with a grain of salt, I can't discount the fact that my experience with the pickups was in two separate guitars--his is a basswood Ibanez, mine's a mahogany Schecter). But yeah, it's a very tight pickup. Does the crunch sound very well, is solid on leads, and has more body than the Pegasus. Clean sounds are a little stiff though. I can't really speak on the Perpetual Burn, because I've never tried it, or have even heard it all that much to be honest. But yeah, like I said, it really depends on what you personally are going for so I can't suggest one over the other.
*I say that it wasn't fitting into
our mixes. That doesn't mean it won't work for anyone else though. It could definitely be a good recording pickup for others. Might be crazy, since I know it was designed for Prog, but I think the Pegasus could be great for a modern take on that 90's Metallica Black Album sound. Smooth, scooped, high gain, chugging metal. I also suspect that, if stuck in the right guitar, and cleaned up properly, it could make some interesting jazz sounds as well with that low end it has. So how's that for versatility?