Saturation ...well harmonic enrichment anyway...can be fantastic .
Quite a few BIAB RealTrack guitars are WAY too oversaturated - sounding fat & squishy but in a bad way.
Kenny G is amazing and so is Reaper.
I used the PSP Vintage Warmer 2, (combo eq, compressor & saturation), quite a lot until about a year ago. It & Melodyne in the one project caused crashes so I reduced usage and slowly weaned myself off. It works really well and the presets are great starting places. I use the 4K button on my SSL interface when I KNOW I want some subtle saturation & upper EQ enhancement now.
The Reaper Wavedistortion VST is very useful but is also easy to overdo - as are all of them, really.
Gain matching is an issue with "harmonics" too: add more required reduction in level to compensate. Most don't do that automatically.
The BBE Sonic Maximiser was a very seductive thing when I 1st came across the VST. Naturally I overused it. These days it might get called upon in for a single track in one out of ten projects - more often than not it's clean guitars or my own VERY dark vocal.
I do have the BBE stomp box version which works VERY nicely with clean six & 12 string electrics.

Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe