The CrazyCap bottle has two water purification modes: normal mode and "crazy mode." According to CrazyCap, normal mode kills up to 99.99% of contaminants and is suitable for "low to medium contamination," such as from public water fountains and tap faucets. Crazy mode, on the other hand, kills up to 99.9996% of contaminants and is suitable for "medium to high contamination," such as from lakes and rivers. The normal purification cycle takes 60 seconds and the crazy purification cycle takes two and a half minutes.
The CrazyCap also has an autoclean function, which turns on six times per day for 20 seconds. CrazyCap says this periodical exposure to UV-C light prevents microbial growth and odor, and it seems to work. After three days of use, I didn't notice any smells or films inside the bottle. Additionally, purified water from the CrazyCap bottle tasted significantly better than water from the tap faucet.
The CrazyCap bottle is more slender than the others on this list, which I liked. It fits into my car cup holders, as well as the mesh cup holders on my gym bag and backpack. It's a bit taller than the Larq, so you might have trouble fitting it in the top rack of your dishwasher.
Personally, I think the best thing about CrazyCap is that you can buy just the cap, which according to the website fits on many different water bottles, maybe something you already have.
On a single filtered water bottle charge, the CrazyCap will last up to two months, but only if you leave it to autoclean. Manually starting the self-cleaning water bottle purification cycle affects that charge time, though CrazyCap doesn't specify by how much.