I've tried them all. Ozium works. But you need to spray it and then close the door (with the fan running) and leave immediately. Breathing that stuff in will hurt your lungs. Unfortunately for me, the odor beats me down the hallway.
I leave the bathroom window open and that helps. My next bathroom fan is going to be strong enough to lift a Black Hawk off the ground, if you get my drift.
I've tried the poo spray in the toilet. It does work, but I usually carry that around in my purse. If I have to go outside of my house, I will have it available (plus another bottle of Ozium).
At home, I just keep flushing. I think we all can agree that we sit in the bathroom for 10-30 minutes, so I just flush in between sets. As I tell the newbies, Don't let it steep in the bowl like a fine cup of tea. Do a courtesy flush!
Gas smell is tricky, but I usually use Lysol Nutra Air and hope for the best. I don't like Ozium the smell is really heavy and I don't think it really is any better.
For the bathroom however I am SOLD on Poo Pourri! I really works and I have tried other spray in the toilet products and they don't but this really does. If you are staying over somewhere like a small hotel room or someone elses house, the combination of Poo Pourri and an Ozone machine (AMAZING!!!!) and you wouldn't smell a thing! You can buy them on Amazon.
My 2 cents!