Referring to anything as the Holy Grail of [X] is hyperbolic at best, dubious at worst, but honestly I feel like this really is the Holy Grail of Swimsuits. The cross-back strap configuration is unusual and very stable and comfortable. The bodice is not blousy, but not tight, and it doesn't float up in the water or flop around while swimming. The bottom is midrise, has modest but not constraining leg openings, and it covers your derriere properly.
The best thing about this suit is that I just don't think about it while I'm wearing it. No worries about suit malfunctions. No parts of the suit ride up or fall down. No risk of various aspects of my anatomy escaping. It is a solid and reliable suit that still manages to be cute and flattering. An added bonus: after more than fifty years of swimsuit-wearing, it is a blessed relief to finally keep my top bits covered when I have to use the loo.