Who cares what "they" think? If you like it, use it. Not any harder to clean than many other containers designed to hold drink or food - worst case scenario you can always use weak bleach solution (whether or not approved by the manufacturer, I've done so for years without any problems).

I bought one a few years back when I got back into training and needed to drink a lot due to a medical condition. Like it on the bike - love it for running on the treadmill at the gym in winter - my balance is off a little due to said medical condition and that is almost hands-free and better for me on the treadmill - and unlike water bottles, which cost up to $20 each for the good ones, I don't walk off and forget it in the cup holder.��