I don't think it's true regarding Tiberius... made threads here about that, but it's not impossible, and in regards to the Life of Augustus which I recently scrutinized with newly translated text that parallels it.... he seems to of been rather factual.... facts are facts true or false, he merely collected and collegiate them.
I would feel quite comfortable using Seutonius, the only shame comes from not critically analyzing him and cross referencing.... and remember the audience he expected to read this isn't the current one.... they had different needs and expectations than we do.