Hi Perry and welcome. Based on general consensus, Uberti is often considered the better choice for a Sharps rifle compared to Cimarron or Pietta due to their reputation for higher quality craftsmanship, consistent reliability, and overall better fit and finish across their replica firearms, including Sharps rifles; however, Cimarron also produces quality Sharps rifles as they often use Uberti as their manufacturer, while Pietta may be considered slightly lower in quality compared to the other two brands. Uberti #1 and Cimarron #2. Cheers, stay safe and enjoy!

In My opinion the best is the Pedersoli davidepedersoli.com/en/products/1874-1877-sharps

Here's a great thread on your very question, along with video reviews/results. Check it out to help in your decision.
Happy New Year!!!
thehighroad.org/index.php?threads/who-makes-the-best-45-70-sharps.874537/page-2