Value is not usually much different between T1 and T2 notes. However, on some banks, T2 might be a lot scarcer/lower print or will have a name change that makes them more desirable. Some banks will have multitudes of T1 notes known, but very few T2 notes known. This can slightly increase premiums too.
In general, I don't chase one of each type.. I just buy what I can hunt down.