Pros: Easy to fill
Cons: Poorly made
We have 5 of these that we have purchased over the last 2 or 3 years. The rubber stopper doesn't seat well over the hole, so the unit must be assembled while carrying it or the water will spill all over the ground (and your legs). This is an awkward way to carry it. One of them leaks while I fill it even when I try to seat the rubber piece first. While I agree with furbabymum that I feel like I am wasting my money, I haven't found a good product. If I were in manufacturing, I would never consider putting such a shoddy product on the market.
On the up side, I have tried plastic waterers and I like the concept of this one. No threads to cross, no turning upside down to fill it.