Decided to do a semi-scientific, mostly subjective test comparing three cordovan leather tabs against a ballistic nylon tab.  Purchased a Rod Jenkins cordovan tab, Big Jim signature tab and Bateman cordovan tab to test against my ballistic nylon tab.  Hopefully, have the leather tabs by Monday.  RJ tab showed up today.  If not I'll start shooting the ones I have.  Plan to shot a 54# Big River mild D/R longbow, 60# HTD recurve, and 63# MOAB D/R longbow.  As I rehab and strengthen my shoulder I'll move to my heavier bows.  I should be able to shoot the same wood arrows for the first three bows.  So it will be somewhat equal.

Sounds like it will be an interesting test.   It will give that hurt shoulder a good workout too.  Definitely split it up into a few sessions, as you work your way up in poundage.   If you get having fun, it might be hard to stop, and overdoing it will only slow the healing.  That would suck:/

Lots of us have done tests like that over the years.  I shot a glove only.  Tabs gave me fits.  On a whim I tried one of the nylon tabs.  It is what I now shoot.  The particular glove or tab really did make a difference for me.

Leather can be cleaned with Saddle Soap, and then treated with Pitch Blend, Bee Natural or another leather conditioner to prevent drying and becoming grooved and stiff.  The nylon is usually sewn to soft leather and if not kept clean will need to be replaced. Cordovan is nice when new but will harden fairly soon unless cleaned and treated. They are pretty much a draw in my mind.  Another option is the leather glove with an insert made by/for Howard Hill. He used whale bone, but I think the company is using a plastic insert. It has two layers with an inner soft liner and flexible insert to prevent grooving. This glove is used for heavy weight bows over 70 lbs. The few I bought needed to be tightened by adding a thin layer of leather inside along the top side to keep them on my fingers. I also added leather stitching below the original stitching to pull it tighter.  IMO tabs are ok for some, but generally inconvenient if you are trying to get off a quick shot. I used them for target shooting years ago, and most were a cordovan, and some had a rubber spacer to prevent pinching the arrow when drawing.                                                                                                                                                                                                                                                                           

What are you looking to test?

I shoot both interchageably, cordovan may be a touch quieter to my ear. I keep the nylon tab slick buy occaisionally soaking in coconut oil as recommended by maker. I also feel the nylon may be better when wet than cordovan.

Looking forward to what you are testing for- speed, longevity, quietness or maybe all three.  I use a nylon tab for olympic type archery, but prefer a leather tab for everything else.  Here a test for speed done not that long ago.
        https://www.youtube.com/watch?v=ej7JHaj0Y-w

Steve;
I spent some good coin on three different "best" cordovan leather tabs, and I may find the best is still my Death Adder nylon tab.  Mine is treated once a year with coconut oil.  I'll not be testing for speed, due to no chronograph.  I'll test for feel, comfort, and release.  Only have the RJ right now, but others should be here Monday.  I'll test 'em when I get them.  Perhaps after a year I'll report back with durability for the contenders.

I think you may find you do already have the best tab. I have shot Cordovan off and for years, as well as a Black Widow tab. They all work.

When I bought a Death Adder tab and first tried it, I wasn't sure about it. But this spring tried it again and it is growing on me.

My old cordovan start curling up after awhile, I don't like that.

Quite possibly.  Then I guess I'll have a yard sale.

I switched to ballistic nylon tab, I make my own, cocobolo plate with bicycle inner tube for backing. Very waterproof and durable. My cordovan tab would lose its slickness so to speak when wet, especially from humidity.

The RJ cordovan tab looks nice and feels good on my hand, we'll see how it shoots tomorrow.  Who knows the leather tab(s) may surprise me, or end up as emergency back-up, or loaners.

All tabs work pretty well in ideal conditions, over the years I have hunted in places where it rained more than it didn't. Some of those times I had a cordovan tab, other times not and sometimes both.
Towards the end of your testing drop them all into a pot of water together for 5-10 minutes and then dump them out, shake them off and shoot them. Rotate them so that they all get shot with the same moisture level and see which one works best.
I also re-apply coconut oil to my nylon tabs more frequently than once a year, usually every 2-3 months, but I shoot a lot. Looking forward to your results.

That's a good idea.  I might not get that far.

My RJ tab was shot this afternoon.  As per Safari Tuff website I ordered a large based on 2 3/4" knuckle distance measurement.  I should have got a Medium.  The first 3 arrow group was wonky.  Tab just didn't fit.  Had one bad miss(high) and lost a tip.  Trimmed @1/4" off the top finger part of the tab.  Better fit and arrows started flying well.  So far have 50 arrows through it, not really a test, but am getting the feel for the tab.  We'll see how this tab performs going forward.  I have contacted Safari Tuff about exchanging the unused one for a smaller size.

https://www.youtube.com/watch?v=JcFhNhV2djg

According to Randy, trimming to fit is the option.  Will adjust, fire for effect and get back.

I have a Bateman, Rod Jenkins, Big Jim all in cordovan, and have a Death Adder original made for me back in 2007 I think.

I like them all, and use them all on occasion, but the Death Adder is my go to favorite.

I'm trying to give the RJ a fair test, trimming slowly to get a good fit.  Big Jim and Bateman haven't arrived, although shipped.  The original Death Adder I have been shooting for 11 plus years is hard to beat, but I'll put it away until the leather ones have had their opportunity to shine.

I got my Big Jim Signature tab last week and shot it all weekend. So far I love it.

Have a ten rings string and two tabs headed this direction, the race is on!  Looking forward to trying the tabs.