A lot could be said about this topic. It's more complex than it seems at first sight. Some hints, with no special order:

1- to get the 100% coverage on the eco grass, you need to disable the "decay near foreign objects".

2- you can put the density higher than 100%. Just not use the slider but rather type in any number.

3- The default grass that comes with Vue is rubbish, IMHO. There are several good grass items in Cornucopia 3D. Look at stuff from Linda Daireaux or Willy, for example, just to name two. There's a very good grass (not VEG, but VOB) in Renderosity free stuff (or I think it used to be, I'm not sure if it's here anymore) by bigbraader.

4- I would say your grass has too big variations in size and color, considering it's a lawn. You need to go to "Scalling & Orientation" and put "maximum size variation" smaller. Regarding color, it's more difficult than it seems. Chipp Walters had a good tutorial on this. I don't have the right link now (nor the time to find it) but go to www.altuit.com and do a search.

5- Chipp Walters again has a nice pack, called TerraPak, which has a very nice fake grass. It looks good on distant shots but I wouldn't recommend it for close-ups.

6- You have a 3rd alternative, in addition to procedural and eco grass. You can have a bitmap. You can texture the ground (or a terrain) with a photo of real lawn. You have to be careful with tiling, so probably the best results can be achieved by mixing bitmap with procedural on the same material, using a noise or fractal function.

If I think of more stuff to add, I'll do it later.

Happy Vueing! :-)