I like SDRR, it's a steal for the price. I mostly use it for obvious distortion - parallel bass fuzz, ditto on drums, crunchy vocals, fat snares with the tube setting etc, and it does the job well. I like desk on kick and snare, set lightly to round out the transients a touch. And yes, the "tight" button on the desk model eq section does something of a Pultec boost/cut curve to my ears, and I like it for a little bit of extra kick low end. My other 'Pultec' plug is Nomad Factory Pulsetec, I'd say SDRR gives a tighter, punchier low end boost than that but not quite as big sounding and often I prefer the slightly looser thicker sound. Obviously Pulsetec gives you a lot more control, too..
I did try the desk mode on the mix bus once to do what I use Waves' NLS bus for, it didn't pull the mix together the same way to my ears. Can't complain though since that's not what it's sold as. The only thing I'd really change is that the parallel wet/dry mix knob comes after the input gain - sometimes I'll push the input gain right up to kick the distortion harder, want a parallel blend and find that the dry signal is blisteringly loud, which means the useful range of the mix knob is reduced. As such, I usually run it on a separate bus send.
MJUC makes me nervous, because everyone raves about it and I just never seem to use it. What am I not hearing?