MicrostockGroup

I am returning to stock photography after quite a number of years (think kodachrome and velvia).  In those days (that makes me sound old) I was with one agency and things were simple.  Send them the best transparencies and they looked after the rest.  The revenues were good versus the amount of time I put into it.  In the way of introductions I am located in the south eastern portion of British Columbia, Canada and operate an on location digital photography studio specializing in wedding, portrait, commercial, event, sports photography and now adding stock.
I have made initial submissions of various agencies with a fair bit of success in acceptance.  No coin yet but I am sure it will as I increase my portfolio in each location.
My question is uploading to various agencies and which programs is used the most and pros and cons of each?  Right now I am using: Cushy Stock, insyndica (trial), and prostockmaster.  At this point my favorite is Cushy Stock as I can add agencies as I am accepted although I find the program a bit quirky.  I like the look and feel of Prostockmaster although I have not found a way to add agencies to there list, perhaps I haven't played with it enough or it is a limitation of the program.  I just signed up with insyndica on a free membership to try it out and I realize the limitations of the free membership and I am willing to pay for the 'real deal' if I like it enough.
If any of you have used, tried, swear by, the above three if you could list your pros and cons about these three or if there is another that you prefer please let me know.
Thank you and I really enjoy reading the posts here so I felt it was time to dive in.
Cheers, Dave