check for background running apps. perhaps the 6+ has many apps running at the background

if you are running high resolution apps, of course the 6+ will lag behind due to the 1080p resolution compared to 6

It's the problem with optimisation in itself... iOS 5 was sluggished, but iOS 6 was a relief on the same hardware at that time (barring the marred launch of Apple Maps). Apple is trying hard to achieve the balance between performance (especially battery) and form factor (thinness), and right now iOS 8 is not optimised... At least not yet... But then again whether or not they can optimised it at the end of the iOS 8 cycle is beyond us since SJ is in his grave now... Nobody in Apple give a damn about perfectionism anymore...

And Apple is well known for "planned obsolescence" of their hardware, so don't think your iPhone can last more than 3 years with all those upgrades. It's gonna get slower and slower with each upgrades...

Buy Springtomize 3 and reduce the animation speed?

Thanks for the detailed response. I think I'll go down to the nearest store and play with both the 6 and 6+ again before I make my decision.

So do u feel the 'sluggish' thing between iPhone 6 and 6 Plus? OMG, now im thinking to get the 6 other than 6 plus...

Seriously guys. Comparing min sluggishness that u might only notice if actively hunting for it, vs 1.8x battery life and full hd real estate? The first can be minimized by closing background apps when not using, while bigger eye friendly full had screen and longer battery cannot be resolved without help of external hardware.
If u have not used Samsung b with all its bloat ware b4, u dunno what sluggish really means. I know coz I upgraded from s4.

Go figure...

If taking 6 due to size factor and ease of 1 hand use, then surely acceptable la...
But now comparing minimal lag....
Don't getme wrong, u r definitely right. Freedom of speech. Just voicing my humble opinion. Sorry if offended anyone ya

And I am one of those because I went straight from the iPhone 5 to the iPhone 6+ and didn't notice anything until reading this thread....  

noob question here , is all the iphone provided by telcos unlocked ?  so i can use other telco's sim card ? example use a maxis sim card on a DiGi's iphone . i'm little bit confused.

In all honesty, where does the sluggishness actually occur? I honestly can't feel it or tell at all hahahaha.

I play games and use a lot of chats on my iPhone 6+ and haven't once encountered anything that isn't fluid or fast.

after watching the Erica Griffin comparison video (a forumer mentioned it a few posts back), it's definitely not you. if i experience the kind of stutter and lag i saw on her video, i can go crazy man.

Anyone willing to swap iP6 64gb Space Gray, still sealed & MY unit? I wanted Silver color -.-"

I'm still stuck on iOS 8.1.1 and seeing your comments about the greater battery drain has stopped me from proceeding with the upgrade, to be honest!

Why? Because of battery life?