Ask HN: Does anyone have experience with In-Memory databases?

This week, I happened to visit a two-day event on a SAP Supply Chain Management Add-On from G.I.B (their products are great, so I can't help to mention them!). During that event they showcased their applications running on SAP HANA, and damn were I impressed by the speed. Now my question: Does an one have experience with this technology? I would love to see it in production. What about you?