Better to convert voltage at each individual component or convert once for the entire system?
There is no clear winner without greater system specific details. 

If all strips have power feeds from about thesame point them 5V 24A may be OK.
If there is substantial transmission distance then wiring losses rapidly make local converters more attractive. 

You can but well priced 5V high current supplies (Meanwell etc ).
Meanwell reliability/quality goodish. Others TBD. 

5A converters are available at very low cost on ebay/AliExpress.
Reliability is usually OK as long as device ratings not abused and thermal issues noted, but some are not unknown to dislike running close to ratings. 

In either arrangement a fuse blowing crowbar advised. 



If you are in NZ - I have dozens of good used Meanwell 5V supplies :-).
Otherwise ... .