I believe ignition offers better promos here or there. Besides that I believe they are just different skins...I don't play on either but I did win $2,500 on Bovoda several years ago on their $250k guaranteed. Though new management since they sold-out and came back I heard are jerks.
when bovada became ignition (and then brought back the bovada skin later) the pool of casino and sports betting players was increased with the network. the previous poster is right though, the $2500 weekly free roll on ignition is pretty tight.
I definitely think that the sites that are the same site,same tournament's, just have a different name should be banned, I have ran in to "multiple account" issues because of this and have been locked out of my accounts.