The bus ride from Tallinn to Riga on Lux Express was a quick four-and-a-half hour trip in a modern, air-conditioned bus. It was kitted out with power points to charge your electronics and even had free wifi, although it was spotty for me.
I was surprised at the high quality of the bus, because the fare was extremely cheap when compared to train prices. The bus driver made announcements in several languages, including English, making it easy to understand what was going on. Also, the roads were in really good condition so it was smooth riding all the way to Riga.
The only negative aspect about traveling this way was the fullness of the bus. However, who can really blame people for using this transportation to get from city to city? With these prices, it made travel between countries very easy and affordable.