If you could point us to some of those posts you've seen about problems with Simplify3D it would be helpful. Without seeing them, it's difficult to quantify that statement as a valid reason to not buy S3D.

It changed my life when I bought it. I used Cura 'a lot' as well as Kisslic3r, Skeinforge (powerful but mind boggling), Repetier, Pronterface and several others. S3D is worth every penny. I'd bet some of the problems were user error and not S3D issues.

Finally, the S3D team is really nice. If you buy it and don't like it, they'll refund your money. Just write them and ask. I did and that's the response I got. So, over a year ago I purchased it and after days two the thought of asking for a refund was a distant memory. And if you ever have a problem you'll get help generally within a few hours. Try that with Cura.