There really is no pro or con for or against in my opinion. The spring takes up space, but still allows float. We like it just because it controls the shaft while the car goes through it's travel.

Normally w/out a spring we cut the driveshaft to allow a 1/4" of float.

With a spring we still have the 1/4" but we collapse the spring and cut that additional amount off.
Say the collapsed length is 1/2", then that is added to the 1/4" and the total is 3/4".

Once you commit to the spring though, you have to always make sure that it is in there after servicing. If not, the driveshaft will probably be too short and will slip out of the yoke or coupler and tear up one or the other.