Voici un début de réponse trouvé sur le forum outre-manche, lien vers le post
ici.
Extrait de l'article écrit par le membre Snufkin, sur bushcraftuk, dans lequel il compare les deux veste:
"I shall have to compare the Guide shirt to the Swanndri Ranger as that will be the item most of you will be familiar with and, as Bisons website states, the guide shirt was made to replace it.
The Guide shirt is made of a much denser wool in a very nice greeny grey and brown check, that is not as overtly "lumberjack" as some of the Swanndri patterns. It has a grandad style collar with buttons rather than the zip of a Ranger. I'm not fond of zips as they are usually the first thing to fail on clothing. Having said that, I've not had a problem with any zip on a Swanndri product. Still, I like the buttons . It has one unflapped pocket on the left breast with a nice subtle leather patch bearing the Bison Bushcraft logo.[...]
The denser weave of the Guide definitely blocks the wind better than a Swanndri, making it suitable as a mid/outer layer. When worn under a ventile wind shirt it is as efficient as the Ranger. However the more open weave of the Ranger means that it insulates as well but for less weight and bulk, something to consider if you are packing for a trip.
The Guide shirt is comfortable to work in when sawing and axeing. I would prefer double buttoned cuffs, as this would make it easier to roll the sleeves up. A minor niggle for me but if you have Popeye forearms this could be an issue.
It hasn't rained, so I am unsure how the Guide will fair but I intend to update this thread when I've had more use out of the shirt.
For now though, I can say I'm impressed."