I have almost always lived in a house on an alley. Growing up, the alleys were 'sideloaded', if that's a term. In other words, the rhythm of the block was house, alley, house, house, alley, house. Probably 3 alleys to a block, with 4 houses to an alley.
My old house and the one I just built are both on 'backloaded' alleys. Personally, I find the backloaded alleys to be more problematic. In terms of convenience, it's hard to attach the garage to the back of the house on a narrow lot and have much of backyard. In terms of crime, I also feel that this backloaded design enables it a little bit more (something I'm concerned with since there've been at least 5 thefts on our block the past couple of weeks, all from the backs of the houses). My guess is that there are fewer eyes on a backloaded alley, because there are only backs of garages and houses facing it. Plus, the length of the backloaded alley is longer than a sideloaded one, giving more places to hide.
Personally, I'd like to see the sideloaded alleys again. It gets the garages away from the front of the street while (I think) cutting down on crime (more windows facing the alley, plus a shorter, more visible length) and enabling an attached or detached placement of the garage along with a backyard.