What's the best quality of this rootstock?

Carrizo Citrange

I guess, there is no best quality.
"Carrizo" is very compatible with most orange, mandarine and grapefruit scions, and it's moderate tolerance to cold, it's medium vigor and it's medium fruit size, by intermediate to high fruit quality made it one of the most used rootstocks in the world.
It's well adapted to sandy soils with medium to low organic matter and a low soil pH. The typical benching of the rootstock isn't that pronounced as on Poncirus trifoliata but still very visible and a good sign to identify the type of rootstock used. The fluting isn't that strong as on Poncirus trifoliata is found, so the trunk remains usually more round and smooth, and not that wrinkled and foldes as Poncirus trifoliata.

It's not the 'all-purpose' or 'multi-role' rootstock, as once was considered, but as one of the major rootstocks in worlds plantings, had done a great impact on citrus growing.