To answer your question in the easiest way is that yes you can tell a difference between the two. In fact, on the Airtronics SD-10G radio if you are using the recievers that have 2048 resolution on them you have to use digital servos because older analog servos simply cannot keep up with the receiver, and you can actually see the servos "stutter" a bit depending on the movements that you are giving them.

So, does this matter to the end user? This is something that you have to evaluate for yourself. It boils down to does your type of flying benefit from the new precision you will get with the improved capabilities? And more important is it worth the extra money for the more expensive receivers (in the case of the Airtronics) and digital servos? Look at it this way, a Indy race team will spend hundreds of thousands of dollars to gain just a few fractions of a second in increased speed. This is worth it to them because it can make the difference between winning and losing. But for the average everyday driver going to work there is no way they would spend the money because they would never see the difference. Since we are in the context of the Beginner's forum I would safely bet that most people here would never see the improvements this would give them.

Hope this helps

Ken