I own grand for now 4 years.it was on jelly bean at first, then it got updated for 4.2.2 jellybean.it was working fine for 2 and half yrs as I used it as my daily driver.
From 2014 it started to lag which was ignorable for most part.But in 2015 many apps were updated and got new material designs wahich slowed downed the phone.
So I rooted my phone 7 months ago and installed cm12.1 also overclocked the cpu, since then the performance was better many apps became compatible camera app becam fast to load in short
Improved the perforamnce and battery life was above average from casual to medium usage.
In this way you can improve your experience.if u dont want to use then always you can give it to some members who dont use phones heavily.
I am enjoying the sweetest release of lollipop now and I also get many stability updates rom is fully stable. So who currently own it try insatlling cm12.1
Which will definately help you.