On your pros/cons list, changing jobs is a pain. So knowing you will likely drop a Big Box shop job in coming years, you could save yourself the headache up front. Some Big Box shops can be down right savage in how you are treated once you drop a resignation letter, like gutting your clinic but then saying you are still on productivity, and for the remaining 60-120 days your income level plummets while waiting to run down the clock. The other aspect I've discovered is it is draining and a pain to 'build up' a new panel of patients. Some people might like doing new intake/consults frequently, but there is something to be said for having your core of patients that are well established. You do Big Box then to PP, you'll have to repeat the build up all over again.
If you decide to make the leap in the future to a PP, there is no guarantee that job will be available or a similar one in your area of choice - which means you will have to open your own or move. That has its own costs, that could be avoided up front with picking the PP first.
Some people are meant for Big Box shops though. I know one doc I've tried to convince into PP, that could actually take most of their current panel with them, without any contract violations, (guaranteed starting income!), but just won't take the leap. Perhaps you are culturally destined for Big Box shop employment?