We just got these so I can't speak to how they'll hold up, but they appear to be very well made and the material, though not extra heavy-weight, seems to be thick enough to offer some strength with comfort.  These are a nice bright-dark blue if you are looking for Mario/Luigi costumes- perfect!

My 8 1/2 year old is in the 80th percentile for height. His legs and torso are both average in length in that he doesn't carry all his height in his legs OR torso- it's evenly distributed.  He's very skinny, though.  He has recently outgrown size 8 slims in Old Navy jeans but 9's are a little bit long on him still.

I got him a size 10 because of the reviews that say they run small or short. I was worried 8 would not last long on him. The shoulder straps are tightened up and I still need to roll the cuffs twice, so we have plenty of room for growth, which is fine.  But I think the 8's would have fit him fine. There is plenty of room for him to gain weight in these 10's, but I would imagine they would be snug on any child weighing in at the 75th percentile or more. Girth hikes up length when things aren't cut wide, and these are not.