I am a legacy user that has updated to the Gen 4 rev 2.2.58. I now can use either the Legacy app or the Gen 4 app. There are some things I like better on the Legacy app and some things I like better on the Gen 4 app. What realy surprised me was when I found out that if I recorded a program on the Gen 4 app, it also recorded on the Legacy app and visa versa.
As for performance since the upgrade, everything is working fine. There was a bit of a learning curve with the Gen 4, but is wasn’t difficult.