I never tried the blue foam plug filler so I can't comment. I can comment on the PTB (LTP) and the Scotch Brite Non-scratch Pad with straw (coffee stir stix) mods. I personally found that the PTB didn't give the desired results. The Scotch Brite Non-scratch Pad works great but it isn't my cup of tea
I read elsewhere in this forum to use a product, that you can get from Walmart, 100% Polyster Quilting Batt (that is what Walmart carries in Canada). It is very similar to the default filler that comes with pre-filled or blank cartridges from most suppliers.
I continue to use the Scotch Brite Non-scratch Pad with straw (coffee stir stix) mod but instead of the non-scratch pad I am now using a piece of batting as the plug.
Pros:
Very cheap, a roll of 72" x 100" is about $8
Wicking: Excellent
Flavour: Compared to other mods the same if not better
Vapor: Excellent
Throat Hit: Wow!
Leakage: Haven't noticed any
Safe: The filler is washable (like you need to wash it), mildew proof, odourless and non-allergenic
Cons:
You might use more juice but do you want to vape or what?
I do dare say that this filler is

and gets a
Whoever made the initial suggestion to use this filler on the forum, thanks very much. Great tip!