It depends on what you want to use it for??
I used Paint Shop Pro (when it was still freeware!!) for many years through many different versions. I have been using Photoshop for about the last 6 years and now use it exclusively, together with Lightroom.
I use a lot of its capability but there is still much more that I will never use. I have spent many hours watching videos, doing tutorials etc and have picked up a lot, but much of it you will forget over time if you are not using it constantly.
If you enjoy learning how to use things properly then PS maybe for you - if you just want to do a quick edit on your photo's then something simpler (and cheaper) will suffice. Photoshop Elements would probably do everything you wanted.