Wow. Thanks, all, for the responses. Clearly this was a needed discussion. I hadn’t thought about plastic leeching and the microplastic aspect.
I’ve only used plastic bottles from Camelbak or Purist, and insulated ones from Camelbak. The reason these steel ones are interesting to me is their insulation capabilities. In the summer, it gets really hot where I am (Sacramento, CA) and even the plastic insulated bottles can’t hold temperature for too long. Trying to stay hydrated on a long training ride on a hot day is hard when your drinks get warm and they become unpalatable.
It sounds like the spouts/flow rates aren’t too much an issue, and the insulation works. The tradeoff is their weight, but if I’m cycling in 90F+ degree weather for periods of time longer than a plastic bottle can hold temperature, maybe the weight penalty is worth it if I’m able to keep drinking.