Maybe you want to look at these numbers...
http://arstechnica.com/apple/2014/09/ios-8-on-the-iphone-4s-performance-isnt-the-only-problem/
And a final look here. If you read down to the bottom of the article, ARSTechnica says this about upgrading with a 4s:
Despite the problems we ran into, we think the answer for most people will still be "yes."
iOS 8 is a big update, and it comes with a lot of big features. Although the iPhone 4S misses out on Handoff, it can still run extensions like widgets and third-party keyboards, two things iOS users have been awaiting for a long time now. By holding off on iOS 7, you were mostly just missing out on a redesign, but with iOS 8 there's good stuff here that you're going to want if you can get it. Ideally you wouldn't have to trade features for performance, but in our opinion getting the new stuff is worth putting up with the small slowdowns you'll experience.
So they are still saying that you should upgrade.
You can get whatever answer you are looking for if you search the internet enough. The VAST majority of people will not have any issues with iOS8. There will be some that do, but we do not know exactly WHY they had issues. Could be they are doing something very non-standard.
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Just because I'm an Apple user (and I like their stuff the best), doesn't mean I have to blindly praise everything the company does even if it's clearly not good.
In a world where everything is great, the word great doesn't have any meaning anymore.
I do not blindly praise everything they do, and there have certainly been missteps (Siri still has a long way to go for instance), but every post of yours that I read make it sound like Apple is the absolute worst company on the planet.
If that is the case, I can imagine what you might say about other companies that you don't think make the best stuff!