PPS will last longer. I was using PPS on a dirted tank with high light and co2 and the growth was incredible. though, i'm sure if i had gone with EI the growth would have been just as amazing.
PPS attempts to keep the right amount of nutrients in the tank without over doing it. EI requires weekly water changes to remove excess nutrient buildup.
I'm using EI now and trying to get all my crap in order... co2 and new led lighting. that along with EI has me battling some algae. I should stop the ferts for now though.
regardless... no co2? don't bother dosing
Both methods can add more and less and end up being the same, they both add the same things, only he rates are different.
EI does not require
weekly water changes, those are used as an example
Algae and most issues are light/CO2 related, not fert related, there's (with ferts) little risk there.
As far EI weekly water changes, ADA also suggest weekly water changes even without the dosing. But few question Amano curiously. I do large water changes on my more pruned and gardened aquariums, less on lower light and less pruned tanks, maybe 1-2x a month and none on my non CO2 tank unless I need to remove dirt etc.
Ferts are modified to reflect the changes in light and CO2, not one simple rigid method applied equally to every tank, regardless of the light/CO2.
Dosing is meant to be modified after......you get a handle on light and CO2.
If you start at lean limiting starting point, then you cannot tell if it's due to ferts being too low, or if it's poor cO2, or poor lighting.
If you start high, then you can be confident that the nutrients are independent
of other factors. This way you can focus on light and CO2, which is much more important as far as planted aquarium management as anyone worth their salt will tell you.
You can reduce the dosing slow and progressively from there after......you have the light/CO2 dialed it and reduce the water changes or whatever else you feel is an issue. We have nice examples of algae with every method of dosing and nice examples of of planted tanks, but they all add the same things. The reasons why are related to light/CO2, not the fert method so much.