I played Lola from the beginning without using any diamonds and I'm now have 6 from the 11 in room 5 completed.She has a decent progress and the x8 as a reward after unlocking a room helps with the next room.
Cherry is very slow and I decided to buy x8 iNnipple Servers. Wish I didn't because it has hardly go any faster. I just finished unlocking room 3 and now I get x8 after a week of waiting. However because of the bought x8 I already have 512 (x8 for room 1, x8 for room 2 and x8 bought) of the max 1280. So this reward is pretty useless...