Screen is Smaller than OG Focus, Focus S, but bigger than Focus Flash. Same specs has focus flash otherwise..
Top of Line is Subjective has it depends on what you are looking for. Since Windows Os is the same across all phones. it comes down to features themselves. (HD, Camera, LTE, OEM Apps)
But Lumia 900 would be top of line all around with best, Screen, Design and Nokia Support and Apps can't be beat.
Titan 2 would be next because of Camera and Giant Screen.
But if Small Screen is what you are looking for then Focus 2 (lte+ffc) or Flash (because of FFC, no LTE) lumia 710 is nice but does not have a ffc..