yeah the merge deposit bonus is horrible and ends up being <10% rakeback or something and would be almost impossible to unlock it 100% unless you played way out of BRM and just ran like god to play stakes big enough to unlock it.
wpn bonus is pretty good if I recall from when I had a look at it, probably like 30% or more rakeback equivalent so while having the bonus if you also have the 27% rakeback you wind up getting about 50% rakeback or so during that period (as there is an adjustment where part of the rake that goes towards the bonus you don't get rakeback on it).
They have the best rewards program on the market now pretty much, even on stars since their changes the max you get is 30% for supernova which of course requires a hell of a lot of play to maintain versus getting 27% anytime all the time without an amount of play requirement so couple that with the fact that wpn has a big first deposit bonus as well as now and then reload bonuses there isn't anywhere else that match those rewards atm (at least that I'm aware of, the closes would probably be
intertops as they have a 36% rakeback you can sign up for and reload bonuses like every month but would rank wpn higher since the traffic at intertops isn't that great (although I would love to see it rebound eventually) and nor is their mtt selection).
IMO merge pretty just killed all the benefits of playing there when they made changes to their no rakeback, and no leaderboards etc over the last few years. They do have a decent mtt selection though.