The backbone of all online casinos is the software that they are using. There about ten different online casino software companies. Of those ten companies, about six of them are reputable. Of those six companies only three of them accept all players from the US. So far, one is publicly traded on the UK stock exchange.

So even though there are a couple thousand online casinos, they are all basically the same depending on which online casino software they use. For instance, all RTG (Real Time Gaming) branded online casinos feature all of the same slots, blackjack, roulette, video poker, and other casino games. The only difference as far software goes is the logo and how the lobby/graphics are displayed on screen. The other differences are not software related and are very specific to each casino, ie, customer support, bonuses offered, wagering requirements, payout percentages, etc.

The major casino software companies that we will be reviewing below are RTG and Vegas Technologies, who both accept all US players. And Microgaming and Cryptologic, who don't accept any US players. The four casino software companies we review have the best reputation for quality casino games, and reliable content connection.

Of the online casino software companies that allow all US players to play, Vegas Technologies is our favorite. They feature the best slot machines like 'The Reel Deal' and 'The Right Prize'. These are video slots that are spoofs of popular American game shows. They also typically have the most colorful and exciting casino gaming lobbies. Vegas Technology branded casinos are Golden Casino and Online Vegas, which are sister sites of each other, which means they are run by the same group, and Superslots and English Harbour, which are run by the same group.

One of the oldest casino software developers on the web is RTG, which is short for Real Time Gaming. Some of the older RTG casinos had a very bad reputation for stealing/cheating their players. However, since the US passed the UIGEA new companies have taken control of RTG powered brands and the results have provided the Internet with some of the most respectful, well run, beautifully designed online casinos in the world. Their games are very popular with players. Their progressive jackpots are known to hit often and their slots payout big.

Microgaming casinos no longer accept players from the US, which came as a huge surprise to the industry when the announcement was made. The Microgaming branded online casinos feature more games than any other software company's casinos. They come out with four new casino games every month and most of their casinos feature more than 350 of their online games. Microgaming is a favorite for free players because they allow unlimited free play. Sites like All Slots and All Jackpots are two of the most popular Microgaming brands.

As far as graphics go, Cryptologic branded online casinos are tops. No other developer has more sophisticated and stunning almost 3D-esque graphics. The bonus round on their video slots feature interactive scenes. In one a player can fight a monster and either win a big bonus by killing him, or get killed and only win a little something extra. Unfortunately, Cryptologic brands do not accept any players from the US, although US players can play their games for free. Sites like InterCasino and Playboy Casino have won awards almost on a yearly basis.