I don't think you can put all LCCs in the same basket. I find Easyjet runs a reasonably serious operation and you get far fewer complaints than you do with Ryanair. The real problem with LCCs is when things go wrong, you are largely left on your own.
It's also important to know what you are getting and what you are paying for. As others have said, they tend to "nickel and dime" you, so read the terms and conditions very carefully.
Some of the LCCs are fine - Easyjet and Air Berlin spring to mind, but you will need to take time to make sure you're getting the deal you want. If you aren't prepared to do that and are worried about what happens when things go wrong, go for a regular carrier. These days, they are often not that much more expensive.