Should I get normal size nuna sena baby playpen or mini nuna sena? I am worry if mini version is not as stable as the normal size. Please advise.

I have the Baby Bjorn playpen / travel cot and I love it. My BFF has the Nuna sena (normal sized) and it's really lightweight to carry, easy to put up/fold away, sturdy and has two heights, so great for smaller infants as well as toddlers. I would not go for the mini version as your bub will outgrow it really quick.