If I hold with 2 of the same units with a hold effect do I get the effect twice?

Yes, you get the effect twice.

According to Rule 383.4.d.2.a, when you hold a battlefield, the hold abilities of each individual unit present at that location are triggered independently and placed on the chain as separate pending items. Because each of your two units possesses its own instance of the hold effect, each one will trigger separately when you hold that battlefield.