I like well executed flippers and the design and engineering it takes to make one. There's a lot that goes into the design of a flipper and not many people do it well. Pivot and flipper angles and geometry, along with detent all have work perfectly to channel flipping force and energy efficiency. You can easily test flipper design with lightswitch method and push down method. One method may work and the other may not or even both. Therein lies the engineering/design's success or failure. I'm going to catch a lot of heat with this one, but many of the production or even midtech knives that offer a flipper doesn't flip well at all. Example: Himderer: We all know about Hinderer and the horrible flipping action it has. It was like the flipper was added as an afterthought to capitalize on the flipper popularity. ZT's - while better executed than most and do flip open, just not efficiently. I have a ZT0560 and while the knife blade design is spot on, the flipper action is just OK. Opens by flipping, yes, but opens with a whimper. It needs an added wrist flick along with the flip to open tight a and strong. Olamic Cutlery is another one that looks like they got everything right with the pivot easy and smooth. But flipping action is terrible, feels like its holding itself back and opens with a whimper. If these were the only examples I had of flippers, I wouldn't be impressed or like flippers either. HOWEVER,...
The GOOD: Ferrum Forge- These guys at Ferrum Forge make a really well designed knife with an even better flipper. The pivot is smooth, the flipper angles relative to the pivot and detent is perfect, resultantly flipping out like a rocket with no effort at all. Opens perfectly with authority with both lightwitch and push down. BROUS- has has one of the best flipping action I've ever seen and is a thing of beauty. CURTISS- the F3 has one of the best and most efficient flipper action on the market. I think it comes down to the tolerances in which the knife is built.
It may come down to your preference, but a well executed flipper is a thing of beauty, to me anyway.
YMMV.