Just went thru this myself, here's my experience. I use Win 95. My focus is on house layout, not landscaping.
Expert software 3D Landscape designer is cheap ($10) and does some cool things with landscaping, and being able to walk around in 3D. It's ability to design walls, corners etc is clumsy. I had great problems with the scale, my property would not fit nicely on the screen, and the slide control is nonexistent.
Complete Home Designer ($50) is the worst piece of @#$% I ever worked with. It builds walls and things the way it wants to, not how you want to. If you add a window to a wall, and it doesnt fit properly, it just deletes the wall. There is no undo. Contrary to the outside of the box, you just cant enter room sizes, you have to draw them, and it's very hard to get them right. I wish I could return the package, but you can't, after it's been opened!!
Now I'm using Broderbund 3D Home Architect Deluxe (another $50), and I'm reasonably happy with it, but the roof designer is a pain in the buttress. I'm happier with this program than the other 2, and after >$100 in software, and much grief, I'm done looking.
===> My suggestion is if you want to evaluate a package, check out their web site and look at their tech support BBS. The questions/complaints/limitations show up very clearly.