Is gadolinium safe for MRI contrast? I've been hearing a lot of negative things. Any opinion? Any tests to ensure the safety?

Usually. Usually safe if you have no renal impairment or allergies to gadolinium-based agents. A test to ensure safety is a blood test to check chemistries to ensure your kidneys are working properly.
See answer. Gadolinium MRI contrast is exceedingly safe. Severe, life-threatening nonallergic anaphylactic reactions are exceedingly rare (0.001% to 0.01%). The american college of radiology publishes that in one series of 687, 000 doses there were only 5 severe reactions. In another series of 20 million doses there were 55 cases of severe reactions. Nephrogenic sclerosing fibromatosis (nsf) has also been rep.