Oh, forgot about the ground fog myself as well. Sorry.
I have two different types of ground fog units, an Antari ICE-101 and an Aquafogger 3300. Now, speaking from experience, the only way you are going to get real low-lying fog is via dry ice. Fog chillers aren't nearly as good. The ICE-101 is a fogger with a chiller. The fog sticks to the ground, but as soon as someone or something moves through it or the wind blows, it turns into fog, meaning it raises up and stops hugging the ground. The Aquafogger also covers a much, much larger area and spits a lot more.
The Aquafogger is a full blown dry ice monster of a machine. It holds 28 gallons of water and 75 pounds of dry with two 1650w heaters, a fan, and a pump (it actually has 4 IEC's that go into it, a 20 amp for each heater, 5 amp for fan, and 5 amp for pump). You can then attach drier hose to it to get the fog to where you want it. With the heaters and that big a holder, they can spit low lying fog for about 10-15 minutes straight before it needs to re-heat. Anyway, these produce true, low-lying fog. The wind can blow, people walk through it, and/or objects move through it and it stays on the ground. Also, when it dissipates, it turns into nothing, not fog like the chilled fog does or as it warms I should say.
Now, dry ice. It isn't actually that bad to handle nor is it that hard to get. A lot of party stores have it and you can get it elsewhere, like food packaging plants for example. Handling it, you simply need to wear gloves is all. To store it, you need a high tech device like this
. Keeping it in a cooler, it will last for a few days or so, longer if kept in a freezer. Its not terribly expensive either. You can get it in blocks or little chips. Blocks last longer, but are more of a pain to handle.
Now, is dry ice more of a pain then chilled fog? Yes, more gear, and more equipment. Also need to get the dry ice and store it. While storing it as well, you need to make sure people don't play with it, because it can and will burn if you handle it with bare hands. However, if you want true, low-lying fog, there is simply no substitute for dry ice that I have seen yet.