Ive got the oxygen mini along with a few others and if stealth is your thing it works great for that. I would always put it in a fast food cup and have the end coming out like a straw. The only thing i dont really like about mine is that you cant get very big hits (on mine anyway). Its always seemed to me that the intake holes are not big enough, i think there is only three if i can remember right. Its been a while since ive used it. My favorite is the herbalaire and it has been ever since i bought it. I always wish i had bought it before the other two. The third one i have is the vapir one and it leaks alot! Ive had to put tape around almost the entire thing. So as you can imagine this one and the mini dont get much use anymore. the herbalaire goes for 250$ I think but it may have gone down. I got mine of thebay for 150$ i think was around the final bid, its been over a year and still works great!
Hope this helps.