I’m certainly no One Drop expert, but I have a Gauntlet and Vanguard. I got the Vanguard first and instantly fell in love with it. The Gauntlet really grew on me, especially after I cleaned and lubed its bearing. It was quiet initially, then got very loud quickly. Problem solved now.
These are very different throws, but I think I’d recommend the Gauntlet. It looks big but plays stable and somewhat floaty. These two YoYos are almost exactly the same diameter, but the Vanguard is a lot narrower. That, plus looking at their shapes, should tell you a little something about their respective weight distributions, relative to the bearing. The Gauntlet is probably the better all around throw for someone learning intermediate tricks, which is where I am currently. I’m a big fan of H shape YoYos and really enjoy the Vanguard, but if I could only own one, it would probably be the Gauntlet.
The latter seems a little more forgiving if I have a bad throw or mess up part way through a trick. Either way, I think you’ll be happy with your choice. One Drop is cranking out one great YoYo after the other these days, so it’s hard to go wrong.