Can you shoot it, first? Be aware, when a Darne fits you, and is in good repair, it compares to shooting a barn hinge gun like night compares to day, skiing to walking, gliding to flying, and sailing to motorboating. It is up to you to know if you are the lover/skier/ glider/sailor type.
If it's broken, or, more likely, doesn't fit, it just sucks. Hence, it is important to know what you are getting in to.
It may seem obvious, but, the people who enjoy them the most WANT to enjoy them the most. An open mind, and adaptability are required, and rewarded with a Darne.
Try, hard, to shoot the gun or one similar before you pony up. Let us know how you come out. The one hard fact in Darne fit is you need 1cm longer LOP in a Darne stock than in your barn hinge gun's correctly fitted stock.
Best,
Ted