This usually makes art take less time and turn out better with more variation. The real catch is of course making things seemless. With the old style of "the edges of isometric are either all one color, or a definite border (the a street curb or dungeon tile)", it wasnt too hard to make it look correct. However if you want more blending for your tiles, such as grass patterns etc, then your artists will have a lot tougher time with it.
The tradeoff with isometric is that isom tiles are a lot easier to make walls and layer things for, as walls are directly at the edges of the tiles so it makes this easy in isom.
-Geoff