Played against that army at 750pts twice couple of weeks back. It was aragorn /w anduril, halbarad with banner and the rest were rangers.
I played goblin town /w some monsters added in as allies.
Both games I got slaughtered. Aragorn ripping through monstes as if they were cake, and rangers /w support and banner don't lose all that often. Did manage to win both however by playing on the objectives, using my superior numbers to ham the rangers in.
All in all i'd say it can be a very nasty army. In any of the more 'deathmatch' like scenarios i'd have lost soundly, whereas i'd consider myself the better player of the two (might just be my ego talking though
). Learning when to spend your 1 might per model is key to victory i'd say. I don't know if it's top tier though. Against a elf army (plenty of shooting, F5 to counter your F4, big heroes to challenge aragorn) i'd say you'd be in trouble.
Better to combine the rangers with the army of the dead. Use warriors of the dead for (slightly more) numbers and a D8 frontline vs archery. A few riders of the dead for some much needed speed. The king of the dead isn't even necessary considering the army bonus! Aragorn and your rangers give you plenty of might anyhow.