Sales do happen, Dan, just not often. There was one this past July and might be another around Christmas. If you can't wait, you can always get a 10% discount off single plugins by letting any existing FF customer send you a referral. PM me, or yorolpal, or cclarry or bapu or anybody else in the FF fan club and we'll send you a referral email with a link to your discount.
Saturn is indeed a lot of fun. It's a tape saturation emu, it's an amp sim, it's a dynamics processor, it's a harmonic exciter. It can add a gentle sheen or mangle sound beyond recognition. I use it primarily on bass and vocals, but it's certainly not limited to those applications.
As an amp sim, there are, IMO, better solutions. Scuffham, Vandal, Guitar Rig are all better amp sims than Saturn. As a tape emulation, there are more accurate simulations (u-He's Satin looks like it'll be the new gold standard). As a harmonic exciter, Ozone is better at that than Saturn. But only Saturn does it all. It's the one I reach for first, even if it doesn't always work out. Saturn is also the friendliest to the CPU, so I don't worry about using it on more than one track at a time.
Probably the coolest feature is the ability to modulate any parameter. This takes some time to wrap your head around, since modulation isn't something we're accustomed to using with distortion effects. But picture an envelope generator tied to the distortion amount, so that the percentage of distortion is higher during the instrument's initial attack, as occurs with natural distortion.