I use the standard OEM slide release on most of my Glocks except for 20. On the larger frame gun the extended 34/35 lever makes it a bit easier to reach. I've noticed that the release is a bit harder to press on my 43. Probably in part be used its new but it also seems a bit more difficult to get my hand in the right position for leverage on such a small pistol.

I'm thinking of trying the Vickers release but Ive never actually handled a pistol so equipped. For those who have, especially on the 42/43, how much difference does it make? I find that the factory extended lever is too long for me on the 17/19 causing my thumb to contact it during recoil.

It's GREAT.  I consider it a must for the G43 (as well as the Ghost Connector and better sights).  
The OEM slide-release/slide-stop IS too small and takes some effort to actuate--the Vickers is perfect because it's EASY to actuate but not huge or obtrusive.

We have them on all of our Glock's.

My thumb rides on the G34 OEM slide release so the Vicker's is perfect.  It's the same length but it sticks out further.

I have them on all my Glocks, but find it is especially useful on my 42.

It's a slide stop

I haven't gotten one of my 43, but I have them on all my other glocks. I think they are a great improvement over the regular and extended OEM parts.

My only concern with the one I installed on my 43 is my support hand pushing it down and not allowing the slide to lock back after firing last round.

That's why I don't use them.  I have big hands and don't need something easier to accidentally ride.  I wish that wasn't the case though because they look like they would be a nice addition.  I love the mag releases.

I ordered one. Should be here next week.

Ran 250rds thru the 43 yesterday with the VT slide release installed. It did exactly what I feared it would do, stopped the slide from locking back every time. On the other hand I examined the stock Glock release and the way I grip the 43 the stock release would do the same.

I have them on all of my Glocks. Im a lefty and the broad surface and texture makes locking the slide back with trigger finger, so as not to change grip, works really well with this.

Same issue for me, and I have medium sized hands. I've learned to rack the slide over utilizing the slide stop.