I'll say its worked great for me...when I was back in Atlanta I had real soft water and had to add EVERYTHING...NO3, PO4, K, Mg, Ca, baking soda...etc.
Since the move to Arlington (and the wonderful Potomic cess pool), things have been much easier.
With higher lighting (the old 46g bowfront) I still had a bit of trouble getting the right fert doses, even with EI.
EI is a good (great) guideline for dosing since the principle is for plants to have an excess of nutrients...thus optimal growth and utilization of nutrients. So long as CO2 is in excess too.
I belive a lot of the problems people may have had/or are having is due to inadequate CO2--plant biomass--micros--macros...in that order.
As far as tinkering with the dosing, I've had to modify it quite a bit since I've moved. With my tap water already at 10 ppm NO3 and around 5 ppm PO4, there's no need to dose on my water change days. Throw in an Eheim liquidoser that was collecting dust in a storage container I decided to dose micros every day rather than three times a week.
I've also noticed small differences in uptake rate of NO3 depending on what type of plants I have. Thus, I only have to dose NO3 one more time during the week and by the end of the week my PO4 is down to 2-ish.
I think is an easy method of fire-and-forget type of dosing where test kits are needed--to an extent...but not the extreme mad-scientist everyday testing such as PPS.
When algae appears I'm a firm believer that there is some water parameter that is out of balance..again this may be attributed to co2, plant biomass, micros, macros. REMOVING algae and correcting the parameters seems to solve problems well.
Just my 2 cents....well I suppose its turned into my 25 cents...
edit...just saw Steve's remarks...hence my reasoning for tinkering with the system...so long as my plants appear healthy, no visible algae, colorful plants, and healthy fish...it works fine for me.