Excuse me if I'm wrong, still a newb waiting for my July batch for my first miner.
Newb question. The 500Mh/s that it mines litecoins, does it mine with 500MH/s other scrypt coins too or the hashrate is different?
The hashrate is the same - doesnt matter what SCRYPT coin you mininig.
Almost every altcoin needs to be changed for Bitcoin and that changed to USD or EUR or whatever - you have to choose coin what has a good liquidity to BTC. It doesnt apply to LTC cos you can sell it for FIAT at Bitstamp and some other exchanges directly.
Many very new arent at many exchanges so the liquidity is low if any.