Over the years, I have tried many bottles, my favorite brand right now is Keego, hands down. My criteria are
- squeezability,
- bounce-back (how quickly does the bottle restore its shape),
- cleanability, and
- longevity.
Keego
This is my current favorite, and my wife loves them, too. They are heads and shoulders above the others in terms of hygiene. The bottle just consists of three pieces, which can be completely disassembled in under one second. No other bottle comes close.
+ The bounce-back is perfect, during the time when I release the squeeze, the bottle has almost restored its shape. That makes putting it back into the bottle cage a breeze.
+ Water flow is perfect with the default nozzle. Keego also sells a large-flow nozzle for those who want more out of a single squeeze.
+ This bottle is by far the easiest to clean. It consists of three parts and can be disassembled within a second, literally (assuming you have already unscrewed the top). The silicone nozzle can be put into a sterilizer and can be replaced. Game changer.
+ The nozzle is cheap to replace and comes in many vibrant colors.
+ So far, the bottles have lasted > 1 year without any degradation.
- The bottles are expensive.
- There is no valve, and liquid may leak if held upside-down. Thus, you have to be careful if you carry the bottle in a backpack or bag.
- Some people find the bottles a bit hard to squeeze.
- No insulation.
- No 1 l option.
- Not dishwasher safe. But then again, you might not need to.
Camelbak Podium Chill
My previous favorite. Still a good bottle, especially if you want an insulated bottle.
+ You can “lock” the bottle. Even “unlocked” it works great.
+ Bounce-back and squeezability are very good. Squeezability is better than the Keego, bounce-back worse. But still very good.
+ Dishwasher-safe (in practice).
- Hard to keep clean. The rim inside the bottle and especially the valve will get moldy. Even a sterilizer (for baby bottles) cannot prevent that. Hence, you get a, hmmm, acquired taste over time.
- The nozzle can be disassembled, but not completely. And e. g. taking off the silicone/rubber mouthpiece carries a risk of it ripping and breaking. Disassembly takes time and is generally annoying.
- The insulation doesn’t work super well. Even if I put lots of ice in my second bottle, it is usually already quite warm when I get to it.
- Price is not great, especially if you include prices for replacement caps.
Over time the valve and all gets
Elite bottles (various models)
Just no. I strongly dislike them. They have been recommended to me by someone, but we simply don’t get along. They squeeze too easily, just taking them out of the bottle cage with the nozzle in the open position typically leads to liquid gushing out. Hence, when I used them, I had sticky stuff all over my bike, trainer mat, just yuck!
+ Inexpensive.
- Way too squeezable, sticky sugar water gets everywhere (bike, hands, trainer mat). Even just gripping the bottle will lead to loss of liquid.
- Bounce-back is way too slow. The bottles don’t sit securely when I put them back.
- The surface is very smooth and the bottles may fly out more easily on rough surfaces than others.
- While the nozzle is better than the Camelbak’s, it cannot (to my knowledge) be disassembled. Edit: The nozzles can be disassembled, but I never figured out how 
Specialized bottles
I’d use these more often if it weren’t for the slow bounce-back.
+ Squeezability is very good.
+ It releases the right amount of liquid.
- Bounce-back is very poor: it is super slow and the bottle won’t seat securely in the bottle cage for a long while.
- The cap isn’t (easily) disassembled. Similar hygiene problem to the Elite and Camelbak.