Absolutely, from a maintenance perspective, having games that are all similar in terms of HW is a tremendous benefit (assuming you are doing your own repairs). Boards and other parts can be swapped between games, either to keep one game going at the expense of another, or as part of the diagnosis process. Additionally, over time, you will acquire deep expertise in the quirks of a specific generation of games since that is what you are concentrating on.
Personally, I like the early Bally and Stern SS games, as the boards between these two manufacturers are largely compatible (some differences in the MPU, but nothing that can't be adapted), and that minimizes the stock of parts and boards I have to keep around. That doesn't mean I'm not tempted to own a Williams or a Gottlieb (I do own a project Black Hole, and would like to find a Solar Fire someday), but by buying mostly Bally and Stern, I've reduced my costs a lot, and also learned_ a lot!