The support person said that I should re-arrange the directory with fewer categories. I should not have to tell my client that 60 categories is too many!
According to two programmers that helped me, the earlier version (Sobi2) did not have these issues. It seems that the 'new' Sobipro is fundamentally flawed and needs to be rebuilt from the ground up to handle large databases.
This review needs some corrections and clarifications:
The author of the review is not very truthful about the number of categories and entries. Actually his site has more than 500 main! categories and not only 60. He wrote in our forum "..we have more than 400 categories and nearly 2000 entries..". And as these are all main categories, we gave him the helpful advice to re-structure his categories to make his site more user friendly.
Yes, there is a problem with the speed in the 'All Entries' screen in administration area. We are working on a solution. Unfortunately it needs some major changes and cannot be done within a few days. We gave him a workaround until the problem is solved. So it is simply not true that we 'offer no help'. On the contrary.
SobiPro is able to handle large directories. The author of the review himself confirms that the speed problem is only in the 'All Entries' screen in back-end.
BreezingForms was initially frustrating (and I've been creating forms for many years) and I was about to give up, but I was frustrated even more with the other forms so I persisted with Breezing and am glad I did. It now easily does what I want (I only use the Quickmode, I'm not sure about the other modes).
I would not have made this breakthrough without sending questions to Markus.