time to complete is much longer

Yes as Uzurpan said and i have also experienced is that boost champ and cut champ are time based and it only takes 60 seconds, so the no. Of tries are more you can even skip the round and start again with the different coins if you are not getting the results you want but space champ is not time based so it takes longer even though after 101 it gets crazy fast but to reach that score it will take i think 4 mins or so which means less tries so that also means low jackpot.

I agree with Uzurpan and Ross.
Even though I always participate, I end up playing it only 4-8 times in total. Ever since I consistently reach at least 101, it takes me somewhere between 6 and 10 minutes to to reach it (I don't remember more precisely now), let alone the silence it demands of my surroundings which is not easily achievable in my case. Most times I play at work, after closing time!
Just like Ross said, with the other games you can simply refresh while playing, and restart instantly. They last only 60 secs anyway. With SpacePan you may have already invested some time and hesitate to restart and go again through the same process.
Yet again, EQ Ace can take 7-8 minutes sometimes and still a lot of people participate. Maybe it's the monotony of the process?

Stelios Mavroyiannis You give 4-8 tries in Spacepan, you have lot of patience. I give a single try and I'm like nahh not gonna do it again. For Eq ace i think it is not that monotonous, we always get different band settings after each hit and plus each week sound also changes so that's better i think this why we get more participants there. Anyways you are doing great in all the competitions, applauses to you.👏👏

Thanks, Ross! I'm doing my best. I'm not that good on Boost and Cut Champ, though. I guess I'm more of a marathoner than a sprinter.
As for the tries, I do 4-8 not in a day, but the whole duration of the contest. EQ Ace is certainly not as monotonous, for exactly the reasons you've mentioned!