I built a house with a slab with floor heat and am building another with a garden basement and floor heat now.  I don;t care for crawl spaces or basements personally. Use pex for water and sleeveitin irrigation hdpe pipe. Use heavy duty cement on dwv plumbing and bed in compacted 3/8 chips. Sleeve your water main coming in.   
 A good slab takes a bit more planing. 
Compaction keeps stuff from settling and thats what causes problems.