The Armisport M1861 is servicable, but it is not equal to the Euroarms version in authenticity. While the Armisport M1842 is a very authentic musket, the M1861 leaves a lot to be desired. The lockplate is way too thin, most of the internal lock parts are not interchangable with originals. Both are oversize in the breech area and weigh 1-2 lbs. more than original. The Euromarms M1861, while heavy, has a correct size lock plate that will take original parts (except the screws). IMO, the best repro M1861 (except for a custom made) is the Japanese (Miroku) made musket. These are out of production now, but come up used from time to time.
Used Armisport M1861 come up for sale frequently. They will serve, but for the price difference, I'd look for a better one.