Hi puneet,
Thanks for liking my post.
It's sad that you were amongst the unfortunate users of
Galaxy S Duos. That phone can get awards for lagging.
And when it comes to screen size I like ~5 inch screen. For example Nexus 5 is perfectly sized.
But I think 5.5 inch should be the limit for
smartphones. Anything above that is overkill.
Now if Display is the deciding factor then you should definitely not go with HTC. Plus as you said you want to use your phone for 2-3 years, hence I believe in that case you should go with
moto or preferably Nexus because these phones, specially Nexus, are bound to get many more software updates.
Whereas in case of HTC you will have to depend on XDA and custom Roms.
Also June-July is a bad time for new purchases specially when Moto X+1 and Nexus 6 (if at all) can be launched anytime.
So could you wait for them launching? You might get your dream deal. See what
Amazon did!