I've pasted a post by llazy llama, hope it helps. Remember since dry contains no liquid you use 20% less. Think about that when looking at prices.
Extract: Dry (DME) Vs. Liquid (LME) Vs. Canned
Dry Pros:
Stays fresh longer than liquid Easily storable, and easily transferred into separate containers. This comes in handy when using dry extract for starters, or for doing partial late extract additions Available for bulk purchase from most any LHBS and most online stores Easy to clean up any spills
Cons:
Tends to clump when added to wort. This is easily remedied by adding DME slowly and stirring constantly Available in fewer varieties than LME More expensive than LME
Liquid Pros:
Available in many different varieties Smells amazing. So amazing, in fact, that sometimes I'll dab a bit on my upper lip, and just be in a heavenly mood all day Less expensive per pound than DME or canned extract
Cons:
You will at some point, regardless of how careful you are, spill this stuff. It's not too difficult to clean it off a stove top (if you're quick about it) but it will make your floor feel like velcro if left to dry. Clean it ASAP To get every last drop out of your container, you'll need to either dip the container into the boiling wort and pour the run off out, or ladle in boiling wort and pour again. It's not difficult, just be careful not to burn yourself as I do every single time Pours slowly. Remedy this by letting the container soak in hot water for a while to thin it out
Canned Extract Pros:
Can be purchased pre-hopped Can be stored over long periods of time without much degradation of quality Container shape is conducive to the dip and pour method to get out every last little bit
Cons:
Tend to be much lower quality. The difference between canned LME and LME fresh from an LHBS or online is very noticeable Can be purchased pre-hopped. Your guess is as good as mine as to what variety of hops they used to make it, or in what quantity Requires a can opener to open. Not really a big deal, in all honesty Pours slowly. Remedy this by letting the container soak in hot water for a while to thin it out Just like LME, you want to clean up any spills as soon as possible Available in very few varities