We run 3 currently and have for the last 5 years. I wouldn't go back to a 21 ever. We also run the Ybravo 25's. Yes the exmark 26 had its problems initially but once you learn their quirks that are different than a 21 they are way more productive. We bag wet grass here in spring and fall and they do a decent job. The Bravo 25 does a better job in wet conditions.
Currently since Exmark is not producing the 26's any longer we are going to their new 30. We will see how that pans out, I am sure there will be issues that need addressed but will be a great mower over all.
What ever I do I must do it right!