Those that do not have SRV Exclusion Zones NO LONGER have the 2 week cooldown !
Find a Base that you like that doesn't have the Exclusion Zone and Scan, Relog, Scan again
This is the 1st usable base I have found, got 15 MEF in the space of 45 mins
I just went to the Exploration settlement Barth's Progress at V816 Herculis and got similar results. I did 12 scans in a row by logging in/out without any cooldown timers. Drop rate for MEF was 33% during those runs (4/12 bases) with each drop counting as 3X MEF again. Average time per run was around 3 minutes which puts the MEF collection rate at about 20 MEF/hr by logging in/out to reset the data points. This doesn't include travel time however, if you factor this in then time to travel to/from the base was around 10 mins each way (one jump in my Diamondback Explorer) which means if you spend a single hour on round-trip travel time plus a dozen data point scans that works out to around 12 MEF/hr. The scans also included around 175k of data point intel packages but given the time needed to travel to Alliance and Empire systems to turn them in they weren't really worthwhile as a source of credits.
This is definitely the best rate we've seen so far for MEF from the bases although I suspect that FD will nerf this back at some point by restoring the 2-week cooldowns. The average rate of MEF drops when you had to travel between each base for every scan was around 15 min./base or 4 base runs/hr which averaged out to around 4 MEF/hr. That is around 1/3 of the current log in/out method which means we can currently collect MEF 3X faster than before (the peak rate would be around 5X faster if you don't include travel times at all and spend several hours of continuous scans at a single base).
Interestingly this MEF rate isn't actually unreasonable compared to other mission rewards. Looking at the mission boards when we are given options for material/data rewards instead of credits FD has put the value for Grade 1 at 25k/unit, Grade 2 at 75k/unit, Grade 3 at 150k/unit, Grade 4 at 250k/unit and Grade 5 at 500k/unit. If we consider the average MEF collection rate (including travel time) of the current method to be around 12 MEF/hr and we've seen that FD values a single MEF at around 500k credits/unit this is equivalent to earning credits at a rate of around 6 mil/hr instead of MEF drops. Even the peak continuous rate of 20 MEF/hr by logging in/out over several hours (i.e., without taking any travel time into account) works out to around 10 mil/hr credit value. Both of these credit/hr values would be considered quite modest considering that players have frequently reported upwards of 50-100 mil/hr credit incomes from various methods (although the extremely high-income methods usually tend to be patched or nerfed at some point). In comparison an average credit income of 6-10 mil/hr is quite reasonable and it was possible to earn 6 mil/hr simply from bulk trading in a Type 9 even before 2.0 launched which means that earning 12 MEF/hr should actually be quite appropriate.
There's also the issue that MEF is valued at 500k/unit when you can choose them as a guaranteed mission reward while the settlement scans only provide a random selection of data drops so we should probably expect a better overall "value" from our settlement scanning efforts since we have to accept the RNG aspect as a major part of the data drop process. At the same time the drop rates do tend to average out over time (especially if you're doing a large number of data point runs that take an average of 3 min./run) and if you also factor in the additional benefit of other random data that we get from the drops (which can be traded at a mat trader) then the RNG aspect generally evens out overall. In general it seems reasonable to use the same value for MEF that FD uses for missions rewards for comparison with the settlement scans, i.e., a credit value of 500 k/unit, even if the actual "value" of the settlement scans isn't exactly the same as other activities. Overall the current MEF drop rate of around 12 MEF/hr obtained by logging in/out to reset the timers probably represents a reasonable time/effort balance for gathering MEF in 3.0 considering the value FD has currently set for MEF as a mission reward. It will be interesting to see what FD does about the base timers because even though the removal of those timers has increased the average MEF collection rate by 3-5X over the prior rate that has really just brought the new collection rate to a point where it makes the data point scans comparable to the mission reward options.