Quote Originally Posted by Meowling View Post
Time blocks is the better option. There's a limited amount of time blocks you can obtain from achievements and well... you have to achieve them, which takes a long time and effort, without which it's even slower to achieve them. As for speed, you can reset the game at the stats to increase it and that's probably the idea, that you keep resetting it to faster and faster.
Assume 120 diamonds, which should be viable, even if quite time consuming.
You can get 20 extra time slots, which is about a 33% increase (60 time slots should be quite easy to reach by that point) or a 64x increase in speed. Later on the time slots may be better, especially if the speed increases are added instead of multiplied (if getting 64x twice gives you a 4096 increase, it's much better than getting a 128 one).