I got a pair of these a few years back. The other I put on my MIM Strat, and the other just found its way onto my old Ibanez Lukather Model after I removed the locking system it had on the headstock face.
I find the height a good thing. They're made of plastic (another good thing in this case), so it's very easy to file off some material to get the desired height. And, as I did on the Ibanez, if you want to mount the retainer closer to the nut than on a Strat, the stock height could be just perfect.
Though they're made of plastic (steel rollers and axle of course) and feel a little flimsy when not under string pressure, they seem to be very durable. The one that's been on my Strat for years (my #1 gtr, gigged a lot) is still like new. I guess the rollers and axle are mount on the body loose enough to roll without much binding, but I think a drop of lubricant every now and then may be beneficial. Not saying these are the best around since I've not tried them all, but they do the job.
by Chris McMahon|
These are plastic
These are plastic. They are not the die-cast string retainers I thought I was buying. Also, they are quite tall, identical, and don't do much to break the string angle on my Strat style guitar.
Sure, they're only $5, but you have to spend $25, plus $7 in shipping to get them.
Thankfully the Warmoth guys are friendly and easy to work with.