Less is More: Coffee Dosing and the Espresso Machine

Wow!  Dosage can drastically change how espresso tastes.  While not groundbreaking for some, tasting the results, i.e. the shot in the espresso, made me a believer in buying a scale in the future.  As of right now, I do not know how much coffee I am using for my double shots.  Is there 18 grams or 30 grams in my portafilter?  Many coffee bloggers, baristas, and coffee redditors propound the virtues of a scale in achieving consistency in espresso shots.  I believe it now.  When I used less coffee, I tasted a full body, pear notes, acidic tingling (good thing), and a bittersweet chocolate finish (I started this post, when I had the Archer Farms coffee, not the Illy).  All of this on my 150 dollar espresso machine, the Lello Ariete.   

Before, I "overstuffed" the portafilter and it would have a nasty habit about once every month to be choked and spit out espresso where the portafilter and the O-ring meets.  Even when it didn't "choke," the coffee seemed more bitter.  I realize the choking can be contributed to fineness of the grind, but when I lowered the dosage at the same grind, the Lello Ariete pulled a shot with no difficulty, and it tasted surprisingly better.  One additional benefit of lowering the coffee dosage, is that it is easier to tamp levelly.  Perhaps, this only happens for me, but this could be a factor for the better espresso extraction due to the flatter and more level surface of the coffee in the portafilter.  

What do you think?  Have you consistently used the same amount of coffee in your espresso or other coffee beverages?  Do you measure by weight or volume? (grams vs. tablespoons)  Is it worth the hassle?