It's good that this is a none controversial subject upon which everyone agrees.
So. I've been trying these halogen capsule based energy savers. I like them.
I put a so-called 60W (claimed) CFL in one of our pair of ceiling roses, and a halogen capsule 60W (claimed - input power 43W) in the other. The difference is outstanding. The halogen capsule light bulb is so much brighter, and.. It comes on when you turn it on. Plus they look good with the clear envelope and the little halogen capsule inside.
I don't think the lifetime of these halogen energy savers will be anything like as good as the CFL but it's worth it in order to be able to see. In my opinion these things are the business. An ingenious way to get the same (or, better, even perhaps) light quality as tungsten filament.
I wouldn't use them in situations where I have to leave a light on for most of the day, like at the top of our staircase (no windows) but for times when you want good light for a few hours or something and you still want to save some energy, I suggest you give them a try.