free all the way. and not just cause i play free in real life. strong is more for run. which is noticed on its position on the field, closer to the line of scrimmage. free plays the pass more.

I notice most high level teams pick one or the other rather than mix (ie two Free Safeties or two Strong Safeties). The exception are the breed of coaches who like to stick two safeties in the middle rather than committing one to either side.

Theoretically like cflames has said the SS is more for support against the run compared to the pass. But you have to be careful applying real life theory to grid-iron application as it doesn't always work out.

Purely anecdotal here (I cannot stress this enough), but I find that two FS tend to give up slightly longer passes but might do a better job 'containing' receivers with fewer home run broken tackle TDs. SS against the g-i pass system is more aggro and sometimes hit or miss. There's a high chance the above observation is just affirmative bias, and it's hard to compare given your opponents change frequently, they also play different tactics even if the same opponent, your players get better, and so on. Sorry to not be able to give a firmer answer.

I'm moderately sure there's not a lot of difference in terms of zonal assignment in coverage though (i.e. an SS on one side has just as much chance being called upon to tackle by the system as if he were instead an FS). Just think maybe there might be a difference in how effective said coverage is.

We'll just sit and wait for project to come along for any firmer information.

I play with a free and a strong. Just feels right for some reason.