GMAW-Pulsed generally has a lower heat input than spray transfer GMAW, while being able to be welded in all positions. With a reduction in heat input, distortion generally reduces. FCAW can also be a low heat input process, as long as the welders are welding fast enough. There are however two general issues:
1) With the slag around, it is easier to over-weld with FCAW than GMAW with solid wire.
2) FCAW is generally a deeply penetrating process. While this is great for ensuring that the materials stick together, it tends to increase distortion on assymetrical weldments.
Hope this helps
Regards
Niekie Jooste