Here is my  comparison:

ProSeries is TurboTax with a few more bells & whistles and no interview to slog through.

Lacerte integrates states much more easily than ProSeries and does presentation to the client in a neater form (e.g. One client letter with federal and every state filed, instead of separate letters for each) Lacerte costs more than ProSeries

ProConnect is Lacerte Online (sorta) but the interface is slower to work through. Lacerte was created before the arrow keys existed and there are several keyboard shortcuts that don't work in this online version. ProConnect is probably aimed at smaller firms than Lacerte.

Here is a comparison of several of the features of each. https://accountants.intuit.com/support/en-us/help-article/compare-products/comparing-lacerte-proseri...