I hope he is immune!
About 4 or 5 days ago I was really fed up with this series due to the highlights constantly focusing on jj and josie, and finding the majority of other hms a bit boring [albeit being nice enough people]. Ben was the only hm who consistently made me laugh, and I was very upset he got evicted.
Sam is like a little lightning bolt let loose about the house, he's so full of energy, a real wind up merchant, cheeky and full of fun.
If I had been Josie with the crotch thing, I would have lost the plot with him, but asides from that I think he brings some much needed vitality to the house. I can see how he could potentially be really annoying to the hms, but so far I think they mainly just find him amusing.
He's made me want to continue watching the series that I had just about given up on, so that's reason enough for me to like him.