They all essentially say the same thing with about the same platitudes.
Keep in mind that references usually aren't critically important at the best of times. No need to give them your grades they (presumably) never taught you, so no point them trying to comment on how you did in history in 1981 that information is on your application regardless. For example, depending on the job, there's a reasonable likelihood they'll be able to comment on your literacy/numeracy at the very least. No harm in having your workplace referee comment on your academic ability, to the degree they reasonably can.
