The only Forstner bracelet I have owned was their flat link and it very much had that “vintage feel.” I knew this going into it and while it is a nice bracelet, I moved it on quickly. If I didn’t already have several OEM bracelets, I would try one of their more robust options (without the stretch links).
I have had a number of Uncle Seiko bracelets designed for Omega’s. They are actually quite universal and fit a variety of non omega watches. I bought them for my Speedmaster but they seemed to be better paired with some of my vintage skin divers. Like Forstners, they have a “vintage feel” and while I know some appreciate that, it seemed a bit of a mismatch in quality to the Speedy they strapped to my wrist.
If your question was “should I get the modern Omega 1171/633 or the Uncle Seiko 1171?”, I would tell you to save your money and buy the Uncle Seiko- they feel and wear exactly the same…
However, since you’re inquiring about the 3861 bracelet… That is a quality bracelet. It’s made well. It has a bit of heft to it because of its build. It’s comfortable. And it’s robust without feeling like a brick is strapped around your wrist (looking at you OEM 1861 bracelet). I ended up buying a stand-alone polished/brushed 3861 bracelet for my 1861 Speedy and loved it.
Yes it is expensive but I do feel it is worth it. Later on, I ended up buying the Hesalite 3861 on bracelet so now I have the brushed/brushed bracelet to put on my 1861 when I want to.
Whatever you choose, good luck in your search and enjoy!