I don't really like these closed polls. I definitely agree with LOD, but I'd have voted for texture atlas and animations ontop of it which both aren't there. A lot of times, you can buy high quality models but they come with 20 diffuse 2048x2048 textures and an equal number of bump and specular ones of similar size which means they aren't really mobile friendly and need a high degree of rework to reduce vertex counts and draw operations. And, lots of high quality animations with custom bones always help, too.