the first years - we use these in the house, but can't really cram one into my bag. my child does take the straw out and, of course, does not know how to put it back. otherwise, they are great.
i have been using sippies for a while. i have not had to replace the valves yet but maybe that is the problem. if that is the case, i'm just going to quit using them. i don't plan on using them for the next kid anyway b/c of the plastic issue (not to sound neurotic - it is just one thing you can control, why not?). i think nalgene is reformatting their plastic formula.
i think you're right - a water bottle is the way to go. why haven't i done this already??? i will have to remember next time i'm at target.
i will look for the playtex coolster. thanks SO much!!!!!