Advice on diva cups

I really like the idea of being more environmentally friendly since I have heavy periods and use a lot of pads. I have heard good things about diva cups but I don't want to spend the $$ if they won't work well for me. I have a really hard time with tampons! I never feel like they are sitting correctly. My sister has a heart shaped uterus and my mom suggested that maybe I have something similar which causes my issues with tampons.

Hopefully that all made sense!

So my question is, does anyone with similar issues have any input on diva cups?