Depends upon the type and alloy of SS you are working with. Some are amenable to conventional welding using GMAW process, while others are best done with GTAW.
For overall, GMAW probably is a better choice for versatility. Filler metal selection and shielding gas mixture will be critical to good quality welding, as with all GMAW process work.
GTAW (TIG) would be best. Thoriated electrode with pure argon shielding gas, purge the back of the weld as well. DC current. This method is slow but excellent weld properties. For reasonably small jobs. For large welds/jobs I agree with last post by Ron.
