Yep they're pretty rad. Some are pricey though for being a small xAAA light. Like the T5S was around $40-45. IMO you could buy a better xAA light for that.
I just got the Nitecore T2s ($24-25) and love it so far, makes for a nice keychain light. I replaced the keyring thing with a more sturdy one, but other than that its nice solid metal.