Don't like small screens as it's hard to see an touch. Tend to go little big but not to big as in just an right size of an screen for an smartphone that is easy to do on it.
My current phone's screen is 5.2 inches which is just fine for me. In my opinion this is a great medium size. Any bigger and for me at least it's too big and awkward. Any smaller and I find everything on the screen to be more congested.
I have a Samsung Galaxy s5 which has a 5.1 inch screen and I think it is the perfect size. I don't like a screen that is too small because it is hard to search stuff online and send emails but I like to hold my phone with one hand a lot of the time so I also dislike phones that are too big. Something like 5 inch is perfect for me which is not too small or big but can also be held and used with one hand. I tried my friend's Samsung Galaxy Note 4 phone and I found is very big, I always feel like I am going to drop it.
I currently have a Samsung Galaxy Grand Prime - 5". I think it is small and I have small hands. Sometimes I can't read things on games. Yet it is easy to fit into pockets
Today I should receive my Asus Zenfone 3 Laser. Which is a 5.5". Which I should be much happier about.
My iPod touch's screen is 4". I think it's the perfect size, and after using other "modern" phone screen sizes, I really do prefer the 4" screen on the iPod touch/iPhone 5/5S/SE.