This is a tricky question which everyone has their own opinion on!!! I use pspx an absolutely love it. I also have pscs but don't use it, unless i want to run a particular action! As far as PSE goes, there is not much difference between it and PSP, so if you are happy with using PSP, then I would stick with it - pse doesn't do much more than psp in my opinion.
I guess if you really wanted to try out pse, you could downlaod the 30 day trial, and have a play with it to see what you think :)