These two series seem to share a lot of the same DNA. Both narrators are lonely, orphaned souls and while John Taylor of the Nightside makes his living as a private investigator with a knack for finding things and Dresden is a professional wizard with a knack, for well, being a wizard, that distinction comes to mean very little in the end. Frankly speaking, if we were pitting them up against each other I'd favor Dresden - if only because he has a dry sense of humor that just cracks me up while Taylor is just, well, dry.
But, this isn't a boxing match and I'm not going to discredit the series because I don't enjoy it as much as another one. And while I will recommend that if you haven't spent time reading either of them Dresden Files is probably the better way to spend your time, I can't say that the Nightside isn't a worthy entry into the genre.
What I will say is this: 'Something from the Nightside' does have some pretty terrific moments: A restaurant that's literally stuck in the 1960's, holes in reality that can bounce you into another timeline and a small group of strong characters that are sure to develop well over the long-haul. The novel also had a surprising ending that served as a great introduction for some additional characters that make a compelling argument to pick up the next book.
So here's the bottom line: If you're all caught up with Dresden, love a good private detective novel (complete with damsel in distress), and don't mind your detectives with a fantasy flair, this one is for you.