What's your favorite cinch that really holds a saddle in place without needing to constantly tighten? I also want it to be soft and comfy for my mare as she can be particular. 

I have a Toklat Flexform wool cinch that I really like except it loosens up so much when I ride. It's soft and cushy, but it's slippery! I have to stop to tighten it a few times while riding to keep the saddle from wiggling. My mare seems to prefer no back cinch so if I'm taking that off I want to make extra sure I've got a secure front cinch. 

I've looked at the Airflex, Aura, Featherflex, or going back to plain old mohair... thoughts?

I sure LOVE my classic equine sensor flex roper style cinch. I always use the roper style. Its super soft but saffle never moves and I have some pretty mutton withered horses. LOL 

I use the Classic Equine alpaca roper one. I've strayed a few times trying others, but I always come back to it every time

Update - found one of my husband's old airflex cinches and tried it yesterday. It was so much better! No slipping and it stayed tight, plus she didn't seem bothered by it. 

Tough one by big horn it's a 5 inch wide medical felt. Not any where near the felt that weaver makes.

I was going to suggest you try an Airflex - I have a friend who loves them. I decided to try one on my really round horses and it does seem to have grip...and the hair and grime goes down in the slots that you can easily clean out.

I use a latigo on both sides of the saddle and tighten the cinch from BOTH sides, that way the cinch doesn't pull up directly on one side, only - I notice it helps especially on a cinch that seems to grip, like this one.

I really like my roper Airflex and the Featherflex. 

I have two of the Classic Equine Aura cinches and they are great. They hold on all three of my differently built horses. I am not a neoprene fan, but these have the soft material next to the horse and do not seem to hold the heat in or be sticky like most neoprene cinches are. 

That's a good idea!

I may try a feather flex in the future too. What differences do you notice between it and the airflex?

These look interesting as well. Does it grip as well as the neoprene? Any issues with hair getting stuck and pulled out in the material or trouble keeping it clean? 

So far they seem to hold really well, but are not grippy like the neoprene so does not pull the hair. When I uncinch the sweat mark is smooth. These can be hosed off or brushed off. I usually just clean them off with my hand prior to saddling the next day. I have a very round backed, cutting bred mare that is much more comfortable in one of these vs. a mohair. The only time I have had one slip was when I used a new pad and I blame that on the pad itself being too thick and not formed to the horse yet.

I think it's the difference in saddles. Both of My dropped rigging Coats can be loose and never move. My dropped rigging Josey has to be tightened and tightened some more. My Ammerman and Courts needed to be snug. Stay away from mohair. I died using mohair one time. 

Roper style cinch all the way.. I feel like it's way more even and more comfortablely snug under the belly. I love the Toklat brand fleece bottom.