If you're using standard screw in cfl bulbs, being upside down in a can helps kill the bulb as the operating temp quickly rises above 50 degrees centigrade.

Isn't what those light bulbs are made for though? What kind of bulb would be better?

Cfl bulbs are generally not supposed to be operated in enclosed fixtures or upside down. At this point in time, lights like the cr6 are more affordable and actually work better. There's quite a discussion on those things in the recessed led lighting thread.

If you have a volt meter check the voltage at the different fixtures. Especially at a "cold start situation."

We've had CFLs in our cans for years and although they seem to last longer than incandesants they do last 5 to 7 years (I date them with a magic marker when installing).
I have called the manufacturer and received a coupon for a replacement.

I've checked out the cr6 and they're fairly pricey. I like that they seal the can though. Can they be used on the same circuit as the CFL lightbulbs? It would be nice to spread out the cost as the CFL's burn out unless all on a circuit need to be done at the same time.

Lowes recently had a sale on these. Are they the same thing? The guy at Lowes didn't know.

No. They use more power (though are a bit brighter) and since the specs say nothing about color rendition, probably won't give off as high quality light.

The CR6 can be used on the same circuit as CFLs as long as there are no dimmers controlling the lights.

As Lee676 said, they are not the same thing as a Cree CR6.

The Sylvania RT6 is not the exact equivalent either.

LED lighting is more complicated than incandescent lighting where the light emitting part is a heated nichrome wire.

Where do you normally get the CR6?

Home Depot for the standard versions (575 or 625 lumen output). Online for the higher output / different color temp. e.g. - polar-ray.com, ...

I switched out 17 cans to the Utilitech LED retrofit. I'll never look back.