I used the ones from Pier One Imports but had to stop. They were very strong and would give me a headache. But the scents were very nice and I wish I could use them.
I've never had any luck with any of these. I bought an Inis set locally at the beginning of summer and never could smell it. I used to get Pier 1 but even those wouldn't smell after the first week. I've yet to find the perfect one that lasts.
I've had reed diffusers I like usually from Pier One, they're no longer on business. With reed diffusers you have to turn the reeds upside down every few weeks or so.