if its just for personal use, the password probably doesn’t matter.
if the containers are strictly for organizing your hangar (you aren’t going to be moving the entire container anywhere, just its contents) I would recommend using the station containers.
the only advantage to the smaller containers is that they actually have more storage space than they take up. (somehow) so if your transporting large amounts of small items in say an iteron V, using them lets you cram just a little bit more cargo in.
Large standard container = no password. capacity 780m3, volume 650m3 (afaik there is practically zero reason to ever use these, no password and the worst storage capacity)
Giant secure container = can be password protected, capacity 3900m3, volume 3000m3
Enormous Freight Container = no password, capacity 250000m3, volume 250000m3 (this is what I would use if I was planning on shipping the whole container full somewhere.)
Station container = password protected, capacity 1000000m3, volume 2000000m3 (these are strictly for hanger organization as they are too large to fit in any ship while assembled. this is the smallest version of this type)
Station warehouse container = password protected, capacity 100000000m3, volume 10000000m3 (largest version of the above)