I still use AGSQL on my older sites. I see no reason to upgrade unless there is some key feature that you are awaiting and that you know is in the works. That's the only downside for me - knowing that they'll be no more features added to AGSQL which would further simplify processes.
Overall TGPX has a little more flexibility in template design and a search feature, but AGSQL is more autosubmitter friendly, in my experience anyway.
So no, no problems here.
