I must say I have never used the Instead soft-cups, BUT, for my periods, I have been using this product for 5 years now, and I love it....only wish I had known about it as a teenager. BTW I don't sell these or get a referral fee, I just think they are so much better than pads or tampons. I will never go bacl to disposable stuff for that, as long as I don't have to!
Also, I do wear it after BD (even before TTC), so that I am not "leaking" stuff out all day, sorry, probably TMI. So anyway, it might be helpful, too.
http://www.keeper.com/
http://www.thekeeperstore.com
Here is a different version, that is clear medical grade silicone:
http://www.divacup.com/
just FYI,
Jess