Both city are very different from 10years back. As we can see there are well develop residential and commercial started growing.
Which one is the best for living environment for kids growing and for retirement.

For me I think KK is better for family oriented living. With parks and upcoming neighborhood town (Rimbayu, Ecosanctuary, twentyfive7, tropicana aman) And a lot of schools nearby.

KK hands down if you are not not from the north or north Klang descendant. The place is smaller and isn't planned as a full fledge standalone city from the beginning. But it is well connected and located closely to fully matured urban area such as USJ, Subang, Puchong & PJ. 30min advantage to KLIA and Putrajaya. Well connected to these places from multiple express ways, KESAS>LDP/NPE, LKSA>Federal, Elite>NKVE/MAX... vs a place that only rely on one way and one exit. And with this connectivity, you are 30min to the best hospitals in Subang and PJ. Nothing beats that for an urban retirement home.

Nothing good about Setia Alam ?

For breezy evironment and for your question, personally prefer KK.

Maybe Kota Kemungin. Apart from all of the above comments, Klang will be getting a LRT 3 line, not that far from KK.

Setia Alam? Nothing but a toll booth waiting for you. And a few KM of jam too lol.

There is no more jam in the morning at Tenby school
They have created a road to reduce the jam

There will b the future DASH highway tat benefits Setia Alam

i've been working in KK area for more then 10years... so, answer is quite obvious..

Distance n time to KL/PJ wise surely kota kemuning. Fully complete township goes to setia alam.

0 points to KK for lrt3. U won't travel further out to Klang to take LRT to KL or PJ. SA is closer to lrt3 in MERU.

FYI none of this KK talk includes rimbayu area. That's a total diff ballgame.

If this is true, probably it's nearer to go to beach from Setia Alam after 30 years
https://www.parhlo.com/rising-sea-levels-malaysia

Im sure everyone will vote for Kota Kemuning as the township and the environment are better than SA. With the very well maintain man-made lake gain point for their project. The only issue if you go for the famous 3 developer projects there you have to round more than 5 roundabout to get back home vs SA one in one out road facing jam issue. Safety wise SA rempit without helmet is the most ignoring.