I had AWS with 1600 hours and yes you kind of need a hearders liscence to operate it. If you keep the linkages tight it wasn't to bad. When you turn feels kind of funny when your back end goes out the other way. You get used to it. If it was the only tractor you used you would never notice it. The AWS always felt wierd for the first bit after running a straight tractor. If you have a lot of oblects in your yard you will like it. The 425 are a good tractor. Keep the linkage tight the nuts do lossen some.
The hydralics / transmission will hold up to lot more hours than that. My brother in law has a straight 455 (Same hydralic / trans system) that he has used mowing and tilling now has 2800 hours. Trans has not given any issues.