hi... sorry to complicate your answer: It depends. Let me explain.
I find more variability of quality due to print shop vs scannings, this is further compounded by types of development, B&W C-41 vs B&W.
I used to shoot alot of ilford xp-2 and I used to go the neighbourhood 1-hour shop. The quality was terrible, brown streaks etc. The lady at the shop was indignant that it was my camera because I was a newbie, the camera was old etc etc etc. But I got better prints from Ruby, Photohub and Konata (in Peninsula). I sort of figured out that a. the chemicals in one hour shops do not get enough refresh. b. the better shops (more expensive ones) have high volume, hence better chemicals and better trained folks.
Scanning has its problems too, many of the shops do not have TIFF but JPEG instead, which is okay. In the end, I decided to develop it myself to cut down the variables and time. Afterall, we have to contend with changes in emulsion (film), cameras, lens, development and scanning. Since early Feb/late jan, I have shot 208 rolls and counting, I neber looked back.
Self-development is a learning curve and only worth it for the hobbyist and those who intend to shoot a lot of film. If not, going to a better shop makes sense.
raytoei