I prefer to use WRP Tool. I used WRP Edit for some time, but switched over after I realised using WRP Tool is much more efficient.
One thing I love about WRP Tool is the Road Tool. It allows you to place vast stretches of road in no time, while in WRP Edit you have to place each individual road piece by hand.
Another feature in WRP Tool I like is the ability to copy/paste and the objects placer. The objects placer is especially handy in making fences.
So if you have Windows XP, WRP Tool, in my opinion, is the way to go. However, as Planck said, it is a matter of personel prefence.