I decided to Cosmic prestige because 2 reasons:
a) Curiosity about how "horrible","tedious" or "annoying" is to Cosmic prestige a Hero.
b) Because the hero I picked has become my favorite and it's suppose that it's "better" to cosmic prestige a hero you like.
I didn't use any boost from the store, all was the stuff you get for free, story and clea FC Mk1, so only the 100% and 50% exp boots, exp cupcake, Cyclops synergy, Godkiller legendary, from like level 52 I used Mole man medallion, and of course this event exp bnus. Here a screenshot (without the leg and medallion, after reach level 60 I got my equip back):
So Yay! but now my impressions about the process:
IMPORTANT: this opinion is based in the current state of the game, I don't know how it was before and stuff.
IS NOT SO DIFFICULT/TEDIOUS AS PEOPLE SAY. When I decided to do this, I was really expecting the worse, based on what I have read here, "you will regret it!", "you probably will hate the hero you picked", "you need to be drunk!", "you will hit your head against a wall!" ad so many other phrases that gives you the idea that you did a HUGE mistake.
Here a screenshot about the time that took me to do this, AND I started blue prestige, since it's the color I like and practically all the heroes I care are Blue:
So as you can notice, took 2 days, better say, two nights, because I didn't play all day, from lvl 1 purple to lvl 60 Cosmic.
The process was NOT tedious at all, it turned slow at level 50 but nothing terrible, and expensive since the LQ re- roll is like 12k or something, when I was lvl 52 I decided to start to earn money instead of lose it, Hightown, earn exp plus uniques I could sold to get more money chests.
The only tedious part of the process was the legendary quests re-roll... that stuff really drain money lol.
Now, after this experience with the Cosmic prestige I realized that several people find tedious, horrible, a torture this process only because don't take the usual hour or 2 to get a hero to 60? LOL? Then I remembered it was even EASIER recently because the "exp bug" and people wanted it to stay that way... wow, really... WOW!
Obligatory: "Back in the days level a character was a weeks/months process!" :P
It's funny, because when I was leveling in Hightown at level 51 - 55 (because then I finished the process in MM because Madness boxes), I thought: so the rush from people about this is because they want to go back and "farm"?, but I'm currently doing that, got some crossbones credentials, and several uniques I used to get credit chests... I'm already farming! and in case I get a perfect unique for my hero, I can use the crafter to make it level 60... I'm not really losing anything... Now that I'm 60, I will go back to hightown to farm uniques to get more chest for re-rolls, prestiges, etc... But I suppose people get all this different, instead of see the bright side of things.
So? I will do this again? Sure, but after I get more boosts and find a hero that steal all the attention American Dream have lol :P
TL;DR: People these days are crybabies.