It's my understanding that limit is popular at places like the Oaks because No Limit was not allowed for a while, until there were means of getting around it (Oaks has 'cap no limit' for example -- can't bet above the max table buyin; Bay101 has something similar). I see the current popularity as a function more of inertia than of actual interest. A majority of the tournaments and SNGs that the Oaks runs are no limit.