In describing a multiple of an element in a claim, is it better to use "at lease one" or "one or more"
They are very likely to be interpreted as interchangeable, but claim construction is subtle, complex and ever changing. You should think about the other words and the ideas behind your claims besides these words. One point is that if you claim your invention comprises "one widget", it covers version that have 100 widgets becasue it does have one. If you said it "consists" of one, then someone who has two is outside your claim.
Also, it has been ruled that "a widget" means "one or more widgets".
Beware of "each" in this context. "one or more widgets, each of which has an X" has been taken to exclude as an infringement a system with some widgets that have and X that includes even one widget that does not have an X. Because it isn't true that each of the widgets does have an X.
google "a gantry at each treatment station" ― "a gantry at every treatment center in a system where there is a plurality or more than one treatment station." Optivus Technology, Inc., et al. v. IonBeam Applications S.A., 2004 U.S. Dist. LEXIS 30314 (C.D. Cal., Aug. 31, 2004).
"At least one of" has been an issue when it is in the form of "at least one of A and B". A PTAB decision Ex parte Jung, 2016 says the plain meaning of this claim recitation is “at least one of A and at least one of B.”)