First grow strain recommendation?

Hey guys just about to embark on my first grow now :D just stuck on what strain to get. I was thinking Devilmatic or polar express but hey, why not ask some experienced growers first? Anyway i do have some limitations.

First of all the strain needs to be autoflowering
this is because i have very limited grow space and so cant have a plant that will grow to big 50-60cm being that max

second i need a strain that isnt to hard to grow, as this is my first time.

and third i need a strain that will yeild a decent amount despite the smaller stature.

Many thanks
GH