Yes, Fastrac is a good choice! I know people who like the 4000 series because of its full suspension and maneuverability!! Models from the 8000 series like Fastrac 8330 is also a good option if you have larger operations.
The Fastrac 4220 I heard is a very versatile machinery, It could even go through wet and soft soil like I read from the other post. I find a very good versatile heavy equipment. Pricey though like @airheads65 said, but I think it's worth the buy..