Lets see:
I have had turfs, R4's and R1's on my Kubbies. On my smaller tractors I always got turf tires, but as the tractors grew so did the tread. My 3710 and my 5030 had R4's and my M9 has R1 radials. R4's wear longer than R1's, much longer especially if you drive them on pavement. R4's ride nicer than R1's, but R1's clean out better and you can specify the tread angle on R1's too. The steeper the bar angle, the more agressive the bite is.
R1's don't cut it on the lawn, they actually "cut" the lawn with hash marks. R4's will mark wet soft grass too, especially with the FWA engaged. If I wanted a good all around tire, I'd get R4's and if it got really sloppy, chain them up.
Skid loaders have had R4's forever and they tear up grassy areas like nobody's business. /forums/images/graemlins/grin.gif