I wear the revival linen gambeson under maille, and it's very comfortable. I added leather points to the shoulders for attaching my arm harness when not in maille and it makes a great foundation garment. I learned the hard way on their pourpoint that the 'point' holes require reinforcement as well, as I blew one out with my leg harness. Just added some leather with holes punched and it works great now.
If you're considering getting a separate pourpoint for leg harness beneath your gambeson, be advised that it must fit very tightly around the hips to support the weight of leg armor, otherwise the weight will be transferred to your shoulders and be much more fatiguing. The problem I had, is even the small from revival clothing is not really designed for someone with a lean build. I have a 31'' waist and athletic build and it's hard to get it to fit snugly in the hips without the center seam meeting (which defeats the purpose).
The best way to go if you're willing to save for it, is custom. Then you know it will fit and function properly. Arming clothes are the foundation for your armor to work FOR you not against you. Even though the revival stuff is built tough and made the function, it may not fit perfectly, and for the price, you can step in to something custom if you wanted. Unless you happen to have the body type that a manufacturer had in mind when they designed an off-the-rack item, you'll ultimately be hampering yourself. For some reason, the medieval re-enactment world seems to frown upon making off-the-rack designs for people who are lean and in shape or skinny, and you'll have a hard time finding things that function seamlessly with your armor.
When it comes to normal clothes you can get away with a less than ideal fit. When it comes to arming clothes, poor fit means fatigue, armor that feels cumbersome and uncomfortable, and potentially dangerous if it limits your movement.
This is Jessica Finley's custom garment shop, and she does outstanding work on gambesons and arming clothes of all varieties. If you're in it for the long term, she's worth the wait.
https://www.facebook.com/pages/F%C3%BChlen-Designs/107298642681955