dryvit is a brandname of EIFS systems Exterior insulating finish systems.  They put on sheets of white styrofoam with screws that have big plastic heads (called windlocks) and then put on a rollout mesh and trowel a gray base coat over it, then finish
it with the finish coat wish is latex, and like brownbagg said besically paint with sand in it.  
 
Stucco is put on over wire mesh which is attached to the sheathing and felt paper,

then the do a multiple coat system, some
types 2 coats, some 3 coats and stucco is cement based
 
Traditional Stucco is a hardcoat system, usually felt, metal lath and
then the cement scratch and brown coats. That can be finished
with an elastomeric paint (to bridge cracks) or a troweled on finish with
texture. EIFS adds a layer of insulation which is encapsulated in the
cement basecoat with fiberglas mesh embedded. The cement is
polymer modified so that it can "flex". The finish coat is then troweled
over the surface. Most new systems include drainage to allow the
moisture out of the wall. Good flashing details are important.
Heres the flaw: Maintaining the caulk joints around windows and
doors. It doesn't happen. water gets in. At least the new
systems allow water out.  The added benefit of EIFS is the
extra insulation. I guess it depends on what part of the
country the house is if that is an advantage or not.

Synthetic Stucco/Dryvit

1.       Made of Co-polymer Resin 

2.       Uses sand or other aggregate to achieve the look of Cement Stucco 

3.       Resistant to water 

4.       Crack resistant 

5.       Color fast 

6.       Comes  wet in pails 

7.       Spread with an acrylic trowel 

8.       More appropriate for dark colors 

9.       Able to have smooth to very heavy textures 

10.   More expensive than cement stucco 

11.   Can be used over brown coat or in EIFS (Exterior Insulation Finish System)

Traditional Cement Stucco

1.       Made of Cement and Lime 

2.       Uses different size sand to achieve different finishes 

3.       Highly vapor permeable 

4.       Comes dry in bags 

5.       Spread with steel trowels and floats 

6.       More of a “natural look” 

7.       Less expensive