ASIC miners only mine SHA-256 and not scrypt coins. Most of the alt-coins coming out at the moment are scrypt based. GPU, cheaper and easier to setup - but power hungry. Mining is a 24/7 job. You will always be wanting to check on your miners status, making sure it is working. There is a lot of tweaking as well depending on the GPU cards that you buy. 7950 or 290 are best for buck at the moment. But with the massive media coverage at the moment the prices for the cards have skyrocketed. When I bought the cards just before every man and his dog jumped onto the scene you could get the cards for around $250/300. Now you are looking anywhere upwards of $500.
Mine alts and trade up! Be ready for the dumps. You have to be watching the exchanges and see when new coins are added and get in quick. Once it's been dumped it's all down hill from there for most coins.