We are building a house slab on grade (no basement) and would like information on whether we need gutters-the pros and cons? Including things we should do if we choose to not use gutters.

Pros:
-directs rainfall away from your foundation
-helps keep you dry when entering your home


Cons:
-cleaning them unless you install "gutter helmets:

nikosmom is correct. Gutters are a must unless you are building low slope roofing with drains. Foundation problems are a terror to repair. Water problems are just as bad. Gutter guards/helmets are great for heavy wooded areas where leaves are a problem.

A con not mentioned here , if you have mulch beside the house or grass and plantings the rain will make a demarcation line along out from the wall of the house. It looks like a stripe and will also cause a depression in the grass line.

Too much water falling from the roof and blowing rain on top of that could easily cause a window leak that you will find out later the hard way.

If you live in very cold climate, it is sometimes a good idea to forget gutters because of ice dams.

Gutters don't cause ice dams at all. Its poor insulation close to the eve that's the problem.

http://www.statefarm.com/learning/loss_prevent/learning_lossprevention_icedams.asp

Why wouldn't you want gutters? Do you need foundation problems? Guess you do.

Just choose the larger downspouts instead of the smaller ones and the gutters won't clog up with leaves, etc. as most of the debris will be flushed down the downspout. Most people cheap out and get the smaller diameter downspouts and end up with clogged gutters.

Put up the gutters even though you are on a slab. Gutters will redirect rain from your entrances and also make leaks at drip edges and windows less likely. If you don't want to clean them you can buy a very inexpensive version of gutter guards at Home Depot. Menards recently sold 10" sections for $1 after rebate and regular prices are about $5 per 10' section.