I voted for what I use, the SD, but in truth it does lose a bit of low end. Well, what really happens, as it seems to me, is this:
The OD adds harmonic content in the mids, upper mids, and some highs. It adds volume in those frequency bands.
You set the OD to "unity" gain, compared to your clean signal, in that process you are compensating out the added mids and highs, so you wind up "losing" low end.
I have also noted, on my Streamliner 900, that added distortion just seems to sap some low end power all by itself. What I mean to say is that I am beginning to doubt the idea that you can add distortion/OD and not lose low end unless you have some sort of active EQ boosting the low freqs.