I love this thread so much I decided to register to these forums even though I'm not a bass player but would love to give my input as I'm currently in the same position as the original poster; in search of that perfect strap.
I'm a guitar player of over 15 years and have owned and played many different guitars over the years of various weights, shape and sizes.
I would like to share my experiences:
A precursor:
It starts with the instrument, much more so than the strap.
After years of playing and owning many different guitars of different shapes, brands, sizes and weights I still always had some soreness overall. Even with what most people would consider a light guitar at 7lbs, I couldn't handle it after a 2 hour rehearsal without feeling some pinch or some fatigue. I have come as close to building my own warmoth telecaster that weighs in at 5-ish lbs. I sourced the lightest body, the lightest pickups, the lightest hardware etc, I went through many many hours and days of painstaking googling to find a way to make this guitar as light as possible. Long gone are the days where I used to just suck it up and play my 13lb Les Paul standard because of the 'mojo' and wearing myself out every gig because of it. Don't settle for the 'tone' if it means sacrificing your health over it! This helped greatly but not completely. I also own a strandberg that weighs in at 4lbs! And unfortunately, as light as she is, after long rehearsals I still FEEL that soreness coming!
And so, the search for the ultimate strap continues:
I have tried many many many straps to this day and have come to conclude that it's very very subjective, certain straps will work for others while some will not. Because everybody's body is built differently and everybody has different tolerances and different levels of tolerances. And to note, I have no history of any serious neck or shoulder injuries. Here are my opinions.
I need something that will make me 'feel' like the guitar weighs less. Or at least feel like the weight is distributed better somehow. So that one can rehearse and play 3 hour sets without aching and needing to go to the chiropractor the next day. A leather strap, especially a quality one like a Moody, which I've had, weigh nearly 3lbs on it's own vs something like a neoprene or nylon strap, which weighs nothing. So HOW can one say that their heavy leather strap that's 3" wide, helps with reliving shoulder/neck fatigue? You're adding MORE weight to the TOTAL weight of the guitar with that heavy strap! It's illogical to the goal I'm trying to achieve. The 3" or 4" width helps, yes but NOT THAT MUCH in relation to the overall weight! That, or clearly, my definition of comfort is NOT the same as the ones who vouch for heavy leather straps.
I've had 2 moody straps, tried the gruv gear solo as well, they were all just too heavy, and NOT giving me that 'weight reduced' feeling. Not worth critically reviewing in my opinion.
The only straps I currently use are comfort strapps, I have found them to be the most effective SO FAR. Even when compared to the Mono Betty Strap, which I've also tried, and although is sturdy and feels quite good, I felt the comfort strapps were just a bit more comfortable. I have both the guitar version and the bass (wider) version. I use the bass version for my telecaster, and I use the guitar version for my strandberg. They are comfortable, the feel is nice and it doesn't cut into my neck like the gruv gear did. The design in my opinion is a bit basic. And in terms of durability, it's definitely not water resistant, in fact it seems to soak up all my sweat from shows but after drying off, returns back to normal. So i'm not sure. It can smell funky too if not cared for properly. The unfortunate thing, is that although these straps would probably be sufficient for most, for me, after 2-3 hours of rehearsing, I still feel the fatigue.
To be consistent with JakobT's posts, i would rate the comfort strapp as so:
Comfort: 8/10
Design: 7/10
Materials: 6/10
Value for money: 7/10
I have just recently purchased an ESO Strap. I basically took a leap of faith on this one as there are no real reviews on this. All the 'highly rated articles' they cite on their website from premier guitar/guitar world etc are simple copy and paste descriptions of the product rather than an actual review. I do, however, like the concept; the strap is S shaped so the strap doesn't actually rest so close to your neck, but instead closer to the shoulder. As i find myself actually doing this after long rehearsals with the comfort strapp, in between songs, or whatnot, moving the strap further away from the neck and placing it there for a few seconds or minutes, helps alleviate the soreness temporarily. So it'll be interesting to try this at my next few rehearsals with my tele. And I think many would benefit from hearing a REAL review on this sort of unknown strap.
I also found out about the KLIQ Air cell guitar strap from this thread so I ordered one. Again, this one doesn't seem to have many reviews either, but definitely more than the ESO strap. I'll be comparing them both at rehearsals in the next few weeks and follow up with reviews for both of these products.