For ourselves DH and I added a Prince Lionheart cupholder. The trick was to install the mount on the handle so it can still be closed. We cut away a chunk of the handle foam where we installed the mount. Viola! As for DS, he's pretty little yet and we've only used the Triumph for a few hours here and there. Honestly, he likes the "out there"-ness of the Triumph over his other stroller (a Jeep Liberty Urban Terrain). I also heard that the Jeep trays fit the Macs, so I tried, and while it could work, we're going without it since Theo likes it just fine as is. We do have a strap called a "Mommy's Helper" that attaches a bottle or sippy cup to the stroller that we use to avoid the bottle/cup on the ground game.
Another thing I devised for the Triumph is a counter weight so I can leave a Skip Hop diaper bag clipped to the back of the stroller without having it tip. I simply wrapped an ankle weight to the flexible footrest section of the stroller. I can even fold it with the weight on there!