I have a leviathan with the included speed trigger in my e&l m4, I can’t fault it. I have had an advanced Titan in my ak which is faultless and an NGRS recoil with a Titan advanced which worked equally well.
The leviathan with the speed trigger definitely has a better feel/resistance, in the Titan the lack of a mechanical “break” point is lacking in feel. With the ngrs this is negated as the recoil, as little as it is moves and gives the impression of feedback that is lacking in the aeg.
I believe that the ngrs with The gate or leviathan won’t feel enough of a difference to anyone pulling the trigger (I shoot precision rifles so am a bit of a trigger snob) as airsoft triggers only matter in gbb.
i believe the only difference is in the suitability of the electrical gubbins the system uses and in that respect I have zero qualifications. I can say that being able to use an iPhone to set up the leviathan and not requiring a lead to carry around makes it a winner over the Titan in both respects