This is a big question and depends what you want to do - I wouldnt necessarily agree 2 tables always make sense.
The main pro of 2 tables is that you can change *PUBLIC. So, if your objective is to close your system than this is easier with 2 tables unless you have a tool like ALLOut in which case 2 tables is optional.
From a maintenace point of view obviously having security in 2 environments is extra work - however the fact that you can sychronise security abd finecut is an added bonus.
I would suggest that you view our products via a webinar or trial which help support 2 tables. If you prefer a purely technical chat - avoding all the sales - then feel free to contact me directly.