In my opinion GIMP would be an excellent alternative, if it worked with 16bit files. Until then it is Photoshop CS6, for which I have a license.
Actually I have no problem with CS6, though it was a bit pricey upfront. The Creative Cloud is also an option if you don't mind a monthly fee.
If I had a choice between Lightroom and Paintshop Pro, I would personally choose Paintshop Pro but for one problem. If you work with RAW images then PaintShop Pro is just not in the same league as Lightroom or Photoshop. However, if like my wife, you prefer to work with jpeg images then Paintshop Pro is a terrific photo editor. The tools will take some time to get used to if you are presently a Photoshop user but IMHO they are every bit as strong.
And the price is certainly right.