I don't know if the purchase price for the rF2 beta is a lot of money for you, but I would advise pretending you didn't buy it, and you may be pleasantly surprised when the final game is released. Currently, the graphics and performance is so below par it's almost embarrassing, but I think ISI was forced to release this beta earlier than they wanted to by certain other games/sims coming to market. We're now seeing the slow development pace of a small team; this isn't Electronic Arts but these guys also won't stop until they're happy with the product, and they won't be happy until the majority of us are happy. Can't say the same for EA.
I do believe the final product will be good and unless you're struggling to find money to buy food, I don't really see any reason to request a refund. If you were that poor, you probably would've thought twice about purchasing in the first place, or would've requested a refund earlier.