Cementitious products are probably the easiest waterproofing materials to use. They're readily available from suppliers of masonry products, and they're easy to mix and apply. If you plan to use this material, a long-handled brush will make your life easier. Also, spend the extra money to buy acrylic additive (a white, milky liquid) to mix in with the cement product. You'll get better bonding and a more solid, durable coating.
The chief disadvantage is that cementitious products have no give to them probably because cement just doesn't stretch to any degree worth mentioning. They will stand up fine to a head of water, but will tolerate almost no joint or crack movement.