Doing in-fight-weapon-deployment drills made me appreciate the flipper (IMHO, it's the closest to gross motor skills than any thumb deployment method) and assisted open (less chance to foil blade deployment). I used to carry Emersons but the ZT350 replaced all of them for strong-side EDC. Since then, I've been carrying a ZT561 - even though not SpeedSafe-equipped, the KVT makes deployment easy and smooth.