I find these much more appealing but based on the following:
Cost. These are priced on my server Mordern Rasp 2 to 3 times cheaper then the SBSS.
Costs aside.
I prefer the Mordant because of my current equipment. These provide double the amount of Saves than the SBSS. Which is quiet lacking in this aspect.
The SBSS do have a HP +80 and a Mana +90, so if saves is not a main concern and boosting these is then that gives em an edge. Although note that SBSS give no STA bonus, whereas these are +11.
I choose these over the SBSS, but that is based on my profile.
Rotgeistae Mordern Rasp
Edit: Forgot about the CHA aspect. As a necro I never cared for it, but now I do. Some say charming, simply selling, I don´t really know but I like CHA being higher than lower. These have this bonus the SBSS don´t. And last thing is that the SBSS does have an AGI bonus +7 which I believe helps us casters with dodging. These don´t.