This is definitely the holiday for you if you like temples, waterfalls and the odd bit of cruising on a river. Out of the two countries, I enjoyed Laos the most. The Lao people are naturally a bit reserved, though friendly enough when you speak to them. For example, wandering round the Night Market in Luang Prabang was a joy as you weren't constantly hassled to buy things and you could browse to your heart's content. In contrast, Siem Riep in Cambodia was the exact opposite!
At various stages of the holiday, we had local guides as well as our tour leader and they were all very good, spoke a good standard of English and were eager for you to know about their country. Transport varied from minibuses, to 4 wheel drives, to boats, planes and one very nice high speed train. All in good condition.
Laos felt a bit left behind compared to Cambodia and I liked that. It had a peaceful, unhurried vibe to it (but don't worry, you could always find wifi :-) ). Our guide suggested that Laos was about 20 years behind Cambodia in development. Cambodia definitely felt different but that might have been because we were in Siem Riep, which is a lot more of a tourist destination because of Angkor Wat.
On the whole, I thoroughly enjoyed the trip, though if I'm absolutely honest, by the end of the trip I was a bit 'templed out'. I would have liked to have spent more time in Vientiane.
Highlights for me
Luang Prabang's Night Market, the Ock Pop Tock silk weaving centre (if you're in to craft stuff), visiting villages and meeting some of the many different ethnic groups, Vientiane's fountains synchronised to lights and music at night, the area around Angkor Wat.
Other things to note
1. Water - it's best to drink bottled water. You can bring your own water bottle or just buy a plastic bottle there and reuse it. The minibuses also carried a big butt of water so you could refill your bottle during the day. Hotels also supplied water bottles in each room.
2. Toilets - the hotel toilets were always fine but ones in the countryside could be a bit 'primitive'. Like Greece, you don't put paper down them, but in a bucket nearby.
3. Insects - maybe because I went in December I never found mosquitos or any other biting creatures a problem, but others did.
4. The walk on Day 6 is over very uneven ground. Think loose rocks, tree roots etc. There is a bit of scrambling over rocks and crossing over a stream several times. The local guide will cut you a walking pole from bamboo to help you. I would recommend asking for 2 as they will help you keep your balance and are very useful for the climb out on a dirt path on a very steep hill.
5. Crossing over to Cambodia was easy, just a matter of paying for the visa and filling in a form. No need for a photograph but I had some anyway, just in case. E-visas also worked.
