I have not tried neem on my semps, but have used it on other things. In general, I will use other insecticides as I have not seen neem be particularly effective and I am reluctant to use it in the house. That's just my opinion - I'm not really very familiar with it as I only rarely use it. Insecticidal soap and pyrethrins are usually my first choice for most things.
Anything that comes in the house in the fall gets a bath with both usually alternating daily for about a week. I'm thinking of adding alcohol to the regime as it seems to work against mites fairly well.
Semps and jovis should stay outside - they like the cold.
