Hmmmm. I've watched this thread with growing interest.
I have used a mix of OEM and refillable cartridges for Epson printers on and off for years: C88, R1800, 3880, 4880.
Inks come from MIS (InkSupply.com).
Clogs are always a problem if I am not doing much printing, but I have never associated this with the cartridge used. Clogs have always been resolved by some level of cleaning.
I have used the inner-bag type of cartridge from MIS without cartridge-related problems, although I am now using only the translucent, open "chamber" type of cartridge. It is possible that I had leaks with *one* of the cartridges I bought, but it has not been a common occurrence. Most of the refillables came from various eBay sources.
The only thing I do that might be slightly unusual (and perhaps unnecessary), is put a drop of clear ink base (form MIS) in the cartridge-connecting nipple (making sure there is no air bubble) just before re-installing it in the printer.
Occasionally I clean the "parking pad" with paper towels and some kind of cleaning solution, and then clean the head by running it back and forth over a folded paper towel soaked with cleaning solution. This certainly does not aim for perfection! It just knocks down the slop and excess that can build up.
When/if clogging becomes too frequent or (very rarely) does not respond to software-driven cleaning cycles, I use a set of cartridges filled with cleaning solution, running cleaning and test-print cycles until almost all of the pigment has gone. I then let it sit overnight, followed one final cleaning cycle in the morning. I have only done this with the 4880, but I assume it would work equally well with other printers if the need arose.
Myron
PS I am currently using the type of 3880 cartridge sold by "EasyBuyCanada" on eBay: http://www.ebay.ca/itm/131145360145
I'm pretty sure my 4880 cartridges came from the same source. I use EasyBuyCanada largely because I am in Canada and it makes shipping easier. By looking at the pictures you can probably find the same cartridges from other retailers.