Should I take "One Mind" if I want to continue to play?

Solution 1:

Having played quite far and having read the source code, I can tell you that yes, you should purchase "One Mind". The "downhill" is part of the fun and the narrative of sorts and the negative effects aren't that bad given the many benefits.

All of the upgrades to the grandmothers beyond that point are very effective at raising your CPS/grandma by sizable amounts. This purchase adds the risk of Golden Cookies (the randomly appearing cookies) sometimes having negative effects like losing cookies or temporarily lowering CPS. It also adds a new positive effect that the golden cookies can give as well. The game also adds "wrinklers" which are randomly appearing creatures that will lower your CPS, but once destroyed will yield 1.1 times the amount they consumed so that actually makes them a good thing.

With the exception of some very rare events that are handled separately, all golden cookie events are equally likely so even with all the elder upgrades purchased, you'll still get positive effects about half the time or more. It starts out with negative effects happening about 1/6 of the time after the purchase of One Mind and gets worse later.

Once you purchase all of these elder upgrades, a new, repeatable upgrade can be purchased to stop the negative effects from happening for a time. Once this repeatable upgrade has been purchased enough times, a toggle upgrade to revoke the negative effects indefinitely can be purchased at the cost of some cookie multiplier. If you ever want to get back that multiplier along with the negative golden cookie effects and wrinklers, another upgrade can be purchased to toggle back.

Given that many of the later upgrades and buildings begin costing in the trillions (100 trillion for several of the upgrades), you're going to want to go for as much CPS as you can (balancing cost/CPS as you go) so that you can let it run in the background, collecting for you. Checking in every now and again and clicking a golden cookie (or several in the case of a chain) is worth it too because it can save you hours in the long run.

Solution 2:

Note: This answer applies to version 1.0402 (current as of 2013-12-21)

One Mind is definitely worth it. Let's see the positives:

• Unlocks several upgrades which greatly boost your CPS, especially the CPS coming from grandmas
• Allows you to earn several achievements, which boost your CPS indirectly via Milk and Kitten upgrades
• Halloween Cookies are cheap +20% cookie production multiplier upgrades (444 billion). You get those from popping wrinklers.
• Wrinklers actually increase your CPS because when popped they give you more cookies than they wither. And it has a "stacking" effect the more wrinklers you have on screen. They provide a 6x CPS boost when there are ten of them on the screen. This is great when you leaving your game idling.

The negatives:

• Increased chance of wrath cookies (depending on the grandmatriarch's status) with negative side effects (loss of cookies, halving your cps temporarily). But even then, the wrath cookie has its positives. One of them is a much higher chance of cookie chains. It also can give you "Elder Frenzy," which gives you a temporary boost of x666 CPS. Stacked with ten wrinklers, this will give you huge amount of cookies.

  In my experience (over 25 quintillion cookies baked), the wrath cookie is actually as good as the golden cookie.

There's also an option to buy the Elder Covenant to put a definite halt to the grandmapocalypse at the cost of 5% CPS. This is not worth it when your CPS is over a few hundred billion, as it will limit how you can earn with golden cookies since all their benefits are CPS based.

The bottom line is, if you don't like wrath cookies you can buy the pledge to temporarily halt the grandmapocalypse. This might be worthwhile if you're actively playing and clicking on golden cookies. But if you step away it's best to leave the game idling with wrinklers giving you that huge CPS boost.