LOL.
They don't have an investment option though so they're not really comparable. Dice sites with investment options tend to have bankrolls which can balloon in size if the site proves to be popular so if the site suddenly shuts down without warning (as dice.ninja did) then the damage is usually much worse. Otherwise, most players don't keep large amounts of BTC on dice sites since they tend to withdraw their funds after they have finished playing.
I edited my post, probably after you replied to it, to add:
Seems dubious.
Since posting that I heard from a friend that they don't actually pay affiliates - he signed up as an affiliate and received nothing. So maybe reconsider whether you want to advertise them or not.
I haven't signed up to their affiliate program. Just their signature campaign, that's all. That 5% stuff is probably just a promotional thing to expand their player base. The market for dice sites is quite crowded so it's not easy for dice sites to attract new players. I doubt most people sign up under an affiliate anyway.
I signed up with affiliate programs in the past and never got paid anything. Did your friend manage to get new signups under his account? Did they place any bets after joining? Their official thread is here if you have any queries or concerns.
EDIT: To clarify, I've signed up to other affiliate programs in the past but not the one in my signature. I was wearing the 777coin signature for about two months and never got a single referral despite making ~300 posts during that time. Never got anything from Freebitco.in/Freedoge.co.in or Primedice either back when they still had their signature campaign running.