This discussion about pros and cons of trifoliata seedlings and rooted cuttings is quite hypothetical.
First of all as Ilya wrote, it is practically impossible to root wooden trifoliata cutting. I remember, that someone posted scientific work about it at old forum.
Secondly, I do not know a single nursery which produce trees for field use in citrus producing countries, which use poncirus trifoliata as rootstock.
Thirdly such nurseries, do not propagate so called "hardy cultivars" for zone 7.
As far as I know, only nurseries for hobby growers like Adavo use poncirus trifolita as rootstock for some "hardy" cultivars, (their standard rootstock for the most cultivars is rooted citrumelo cutting I think).
And I do not believe that rooted cutting is weaker than seedling. For citruses, which root well, like pummelos, the root ball is really strong and dense in the case of rooted cutting.