UB is not doing profit sharing. The site that is, is a skin of UB
www.pokershare.com. They are doing a new program of player promotions every 3 months, starting in December, I believe.
They will distribute 40% of their net profit to the players based on their Ultimate Point totals. The formula is a bit skewed in favor of lower limit players, but the site has been very good at following up with any player concerns.
However, 40% of profit is a far cry from 40% rake return.
Historically a business that can make a profit of 10% of gross sales/income is doing quite well. That would translate to a 4% return to players. However, many online businesses have a profit margin higher than that, so I wouldn't be surprised if there were a higher return than that to players.
Of course that is in addition to any site and affiliate perks you can obtain.