Another important note, without having to read the pdf, a fingered device shares sources and drains, therefore it has less capacitance and is faster in terms of fT. Additionally, they take up less area then multiples. The way I see it, if you want better matching at the price of area, you use multiples. If matching can be relaxed, then use fingers for increased speed. If you don't care about matching, area, or speed, flip a coin and pick one..
Just my 2 cents,
JGK