It's just as easy on the arm as a whole gut job, but it has that controlable pop of a poly. The poly allow you to get a tight feel with gut, without strining it all the way to the racquet's max.
I actually think this lasts longer than a whole gut job. As long as you use at least a 16L poly in the crosses, it doesn't fray the mains either.
Oh yeah . . . Using a 3.99 poly in the crosses cuts the cost of the string 40-45%.
. . . Bud