The ROA is wonderful which is why I have picked up three of them over the years. All second hand and all with adjustable sights. These were 'right place at the right time' lucky finds. But unless you need the extra power its larger cylinder allows or the modern, longer lasting construction, I think a Pietta 1858 New Army will suit you well and at a fraction of the cost of an Old Army. Of course, if at all possible, handle any pistol before buying to see if it balances well for you. I have larger than average hands and the 1858 grip feels small but I shoot it as well as any of my Colt repros.
Jeff