I love strippers. Wait, that didn't sound right. Let's try again. I love to use stripper decks in magic performances. They are a great tool with many uses. That being said, some laypeople know the secret, so I wouldn't let a spectator examine it, but if the deck is made well, there is no reason the spectator can't handle the cards.
That being said, the invisible deck is a miracle. The best magic effect for the price. You can hand out the thought of card at the end and that's all the spectator needs to see.
I'd say get both. If you can only get one, get the invisible deck.