I've got Retail Escort and Video Escort, and have used SBase4Pro for ages (well before that version). But I ended up buying Lotus Millennium a couple years ago and Lotus Approach just stomps the living daylights out of SBase - not to mention how well it integrates with the rest of the suite. Actually Lotus seems to be about as Amiga-like as you can get on Windows with productiveware {save for the places it uses those crap Windows requesters ; }
Part of the problem with SBase as it has always been behind in adding Amiga OS services such as screenmodes, graphics card support, and by the time it has gotten interface improvements that reflected the state of the OS, and taken advantage of newer features, it has again lost ground. And then there are the bugs (especially in the form designer), and the errors and gaps in documentation caused by incremental changes and sporadic feature creep. These changes over the past few versions have cleaned up some of the oddities of use though...
I haven't tried it on my Pegasos yet to see if it runs at the level it did on my Amiga, but one thing is for certain: porting to AOS4 is an excellent opportunity to establish consistency in its interface and its use, which will really make its potential more obvious and realizable.