The rivet-type master links require a special rivet tool, to cinch them in place. Last time I checked, around four years ago, this tool was something like $108 + S/H -- a tool you will use once every 20,000 miles? I had my mechanic put my 630 replacement on, with the rivet -- cheaper than my investing in a tool I would have used
once (sold my K model in 2012, after putting only 13,000 miles on it over the six years I owned it).
The clip type master links are safe, just be sure to put it on facing the correct direction (easier to remove the chain, by far, for rear end maintenance -- with the rivet type, you will have to fully remove the rear wheel, and the side cover over the front sprocket, as well). Cheers!
1979 CB750K (sold, 2012, but not forgotten)
1983 Kawasaki 440 LTD Belt Drive (sold, 2011)
1993 Kawasaki Voyager XII