The SOS DanBuoy is v widely used (to the point of it being standard issue) for all rescue
craft (incl helicopters) here...and we suggest it should be on all cruising craft as well, as it is on our beloved CatNirvana
. As others noted, the emphasis on visibility for the MOB is both appropriate and practically essential...and, in our view, it makes the SOS unit very clearly preferable to the units suggested by the OP.
The SOS DanBuoy has been on the scene here for a few years...does anyone Stateside know if it's now USCG approved?