There is a BIG difference between nitrous brands. The problem is that most people only try shitty brands of nitrous, such as EZWhip(the WORST) and ISI(not the worst, but still pretty disgusting).
The BEST brand of nitrous is PureWhip. Hands down this one is 100 times better than ISI or EZWhip.
It is also cheaper, and probably much less harmful to your health.
Supposedly PureWhip consists of 100% medical grade nitrous oxide, put into cartridges for gourmet food use. From personal experience I can say without a doubt that PureWhip contains a small fraction of the amount of machine oils or lubricants or whatever the hell else is in those other food grade brands of nitrous oxide.
The only problem with PureWhip is that I have never seen a store that carries it, however it is very readily available on the internet for very low prices. I used to buy them by the case(25 boxes of 24 cartridges= 600 whippits) for a very low price. I highly recommend buying this brand, it is so much cleaner it is ridiculous. I have personally tested the cleanliness of different nitrous brands with my whipped cream dispenser and my lungs and here are my findings:
After running one box, or 24 cartridges, of ISI through a clean dispenser there was a very light film on the inside of the chamber of the dispenser. After running my finger along the inside there was a noticable amount of oily residue stuck on my finger.
I did the same thing with EZWhip brand, after cleaning the dispenser out. 1 box of EZWhip left about 50% more residue inside the dispenser than the ISI did. This stuff in my opinion has a much worse taste than any other brand. And after taking a bunch of these things throughout the night, the next morning I am coughing up black oily shit all morning. ISI doesn't taste nearly as bad as EZWhip and doesn't mess up my lungs as much either, although it isn't really good either.
Finally I put PureWhip to the test. Using a clean dispenser I ran 1 box through it. Upon opening the dispenser I found a virtually clean chamber. I ran my finger across the inside, I felt a slight oils feeling, but when I looked at it there was no noticable residue. I then continued testing PureWhip, and over the course of a night I had used over 4 boxes of PureWhip in the same dispenser. After having used over 100 PureWhip cartridges in this one dispenser I opened it and examined the inside. There was a decent amount of residue in there, but a little less than what 1 box of ISI had done.
To sum up my findings, PureWhip has less than 25% of the residue that ISI or EZWhip have.
PureWhip also tastes good. I love the taste of these things, I can't stand taking any other brand. Please do your lungs a favor and get PureWhip, you will be doing your wallet a favor too.