I am currently in Laos on Holidays and have been for the last few weeks. Thailand deserves all the talk, its probably the best country in the world to travel in: cheap, easy, beautiful, diverse, adventure, relaxation, party, etc.
Laos on the other hand is hard. Wonderfully rewarding but difficult to travel around. The roads are the worst I have encountered in the world. A 250km bus journey in the north will take 10 hours and that will be crammed in a tiny seat on a hot bus. Nothing seems to leave on time, always takes longer than advertised, and there is no such thing as full.
Don't let that put you off. The easy road that most people do is Vientiane to Luang Prabang (usually with a slow boat to/from Thailand.), will take a week or so and gives a good taste of the country without taking you into the really difficult stuff. If you are up for more adventure then there is plenty to see and its well worth it.
The landscape is rugged and untamed. Full of caves and waterfalls. The UXO situation is a little scary and did stop me doing unguided treks.
I actually like the people better than Thais, they are just as friendly but seem a lot more genuine. The general english level is good in the cities but falls away to nothing in the countryside.
The Lao food can get pretty boring after a week or two. Luckily there are plenty of other good options: Thai, Chinese, Vietnamese, French, and the usual western choices.
There seem to be plenty of people traveling alone but most seem to form small groups in their travels to help with bargaining for accommodation and tours.
Money was the hardest thing for me to manage. There are very few ATMs and they have tiny withdrawal limits (~$100). Bring plenty of cash (Baht or US dollars) and travelers cheques with you.