My answer is always the same. Like land casinos in Vegas or anywhere else, they have more to lose than they have to gain by being rigged. I believe for the most part the games are as random as technology will allow, that is where randomness is the essence of the game such as Roulette and Black jack. The virtual slots are set similar to any slot machine found in Vegas, Reno, Tahoe or anywhere elese in the country. As most know, slots are set to pay back, at least the legal minimum, and up to anything over the legal minimum determined by the Casino.
Available technology can provide similar results.
My answer to a question of Virtual casinos reliability. They told me that they cedit winnings back to your credit card up to the amount of the original debit and mail the rest which takes from 2 to 3 weeks. The mails are unbelievably slow from that part of the planet. Patronize the above casinos and lotteries. The unforgiving internet grapevine.