Okay... I exaggerate. There was no drama, no real smacking going on, and this was a completely non-scientific test with a test comprised of one user and two pots.
Over the course of the past week I have brewed a 12 oz cup of coffee with my V60 nearly every day - alternating between the $60 Hario Buono and the $20 Tiamo.
Pros: Reasonably priced for what it is. Has a heavier, more solid feel than the Hario, the lid stays on tight no matter how far the pot is tipped and it has a narrower diameter for the spout - thinner more precise stream of water.
Cons: Lacks the aesthetic appeal of the Hario, the curved metal top handle lacks the intuitive feel of the Hario's side handle, and it can pick up fingerprints etc. very quickly on a busy bar. If you're loading water directly from a spout the position of the handle will not be an issue, but I was pouring water in directly from a stovetop tea kettle and found it a bit tricky to get all the water in. Also - on occasion a bit of the water comes back up along the outside edge of the spout if you don't stop a pour quickly enough. When making multiple initial pours to get the bloom to rise and mushroom - one needs to have precise down and up wrist action - it's a bit less forgiving than the Hario.
Pros: More appealing from an aesthetic standpoint... plus you can get the cool little matching glass pitcher to brew into. Easier to fill if you are using a tea kettle to fill. Good feel for pouring action.
Cons: Too lightweight relative to size, awfully expensive for what it is, and the lid has to be held on when one tips it far enough forward to completely drain it.
For me... the clear winner is the Tiamo, but with a few reservations. I think the ergonomics that made the Hario feel easier to use would become a non-issue when one became more accustomed to the Tiamo, but if the lid fit more tightly on the Hario and it was priced lower the score would even out or tip in favor of Hario.
See pictures of the two kettles side by side on this thread: