I've been using our playpen for 4mths now. My son is now 9mths and is starting to pull himself up on it to stand. I was worried it may not be sturdy but so far so good.
It's bright and very light (so great to move around when doing housework or in a tight space). Very easy to put together.
I've seen reviews elsewhere about toddlers lifting it and moving it around. I'm sure it would happen because it is that light but my boy hasn't figured it out yet...
Decent size but I'm now thinking of getting the extension for when more kids arrive.
Overall a great product. Not perfect, but great.