I've been wearing Lycra jammers but they deteriorate very quickly so I decided to try a polyester jammer.  I've only had it a couple of weeks but so far so good.  I guess I like the look and feel of Lycra a little better but not significantly.  If the polyester lasts longer it will be well worth it.

Son #1-8 1/2 years old.  Wears an 8. He's pretty atheltic, not chunky. Wears the 28 and it's not tight, just right.It would still fit if he were a little bigger but not much smaller.  Weighs about 65 lbs.
Son #2 - 6 1/2 and short for his size. Also athletic but stockier. Wears a 6. The 24 fits just right, not too tight.  Would also work if he were a little taller but not fatter.  
Material is thicker and lined.  Noticable difference between the cheaper versions.

TYR is DA bomb when it comes to suits.  Some how the other bands always seem to turn in to tisue paper on me.  TYR seems to hold up well with the mystery chemicals that they use at my pool and the stiching seems to hold together well.

I have a TYR polyester suit from 2003 which I still use regularly.  I now have a second copy.  This suit takes regular use in public, highly chlorinated pools.  I am very happy.

I bought for my 7yrs boy, he is a beginner in swim club. He loves the pants as same as i do. It has simple design, and easy pull up and down; I love it lengh, because most of swimming pants for kids are just like short pants. But this design takes a little bit longer above the knees, looks it just nice for him.

Good fit, the material is a lot softer than the speedo polyester suit this is replacing.