Panzergrenadiers are great AI units right of the bat. A Panzergrenadier squad will beat a 2x BAR riflemen squad at medium range and under. From what I see from replays, people often just don't use them the right way. People often use panzergrenadiers as if they were SMG troops, trying to get them as close as possible to the enemy before stopping to open fire. This is simply not how you use them. They will drop models on approach and you will not have the models left to inflict damage. Instead, you should just stick them behind some cover at medium range and watch them do their magic.
PGrens beating 2 x BAR riflemen at medium range and under. No chance buddy.