Ok so after some time to allow some good testing I came to a final verdict about who is the best after about 500 real signups in each.
Casino Classic is the winner with an 8.77% conversion rate.
while Mummys Gold has lost with aa 3.61% conversion rate.
even with their horrible earning model classic can easily beat Mummy’s in terms of bottom line as they have almost 3x the conversion into new players.
BTW I have no idea what they do differently in order to capture 3x more players into new depositors since they are both Microgaming.