Far larger than Don Dhet, Don Khon is skipped by many budget travellers because most of the accommodation is midrange. However although there aren't 40-odd places to choose from as on Don Dhet, there are budget options here and staying on Don Khon is far more of a Lao experience than Don Dhet.
There is a better range of eateries than on Don Dhet and the options for cycling and walking are considerably more extensive. The main disadvantage or advantage depending on your point of view is that it's quieter and less backpacker friendly, with fewer bars and slightly more expensive food.
The island hosts quite a few reminders left behind by the French -- several old colonial buildings, including the school, the French port and French embankment -- a series of concrete barriers built on the eastern side of the island.
You'll also find what's left of the light-gauge train track that used to traverse the island, now a long clear path of heavy gravel. There's a small engine and a length of the old train track on display to the west of the French bridge.
But Don Khon had a good deal to offer before the French ever showed up, which is still on display -- the powerful Li Phi waterfalls on the western side of the island, the Irrawaddy dolphins off the southern coast and scenes of pleasant village life that you can cycle or wander through at your leisure. It's an idyllic place that balances the excesses of Don Dhet with the idleness of Don Khong.