Any recommendation for BTC PM Solution Express?

Having started my practice late last year it's growing to the point where I think I would benefit from having some proper practice management software, rather than using Excel and the contents of my head.

What I'm primarily looking for is a system for managing my workflow - i.e.: something where I can schedule all of the tasks I need to do for each client and when they're due by.  I'm not especially interested in time and billing software as I have no staff (yet) and only charge fixed fees.  I'm not trying to start the old timesheets vs not argument.  In the future when I have staff (and maybe even before) I will want to record time but only so I can sense check fees and make sure I'm not underpricing anything, but that's not a huge consideration at the moment.

I currently use SA Solution Express which has a limited PM aspect to it.  However I cannot add my own tasks to this (I do a lot of bookkeeping, payroll, forecasting, MI, etc for clients as well as the compliance work).  I can't do this with what I already have.

Does anyone have any experience of PM Solution Express?  What are the good/bad points, what limitations have people found, etc, etc.

Thanks in advance