best photo editing software?

Gimp is free and let's you import Adobe projects.  But has terrible filters.

You  may get a better answer if you include your price range. Otherwise, Photoshop always wins.

How much do you want to spend?  

The "best" is Adobe Creative Cloud, which cost $60 a month.  It includes Adobe Photoshop (which you can get by itself for $20 a month.)  But most people do not want to pay $720 a year - every year - for a photo editor.

An alternative is the free program GIMP.  It has been around since the 1990's and does every thing that Photoshop does.  It can even use most of the Photoshop plug-ins, brushes, etc.  Many of which are free,  However it has a very steep learning curve.  It has a lot of options and extra and can take months (or years) to learn all the ins and outs of the program.  (The same is true of Photoshop.)

If you are looking for a quick and easy Photo editor that will do 99% of what most people need, download Paint.net.  It is free, easy to use, and does everything the average person would need for editing photos.

Personally, I have both Paint.net and GIMP.  For most of the day to day things, I use the Paint.net because it is so simple and easy to use.  I reserve GIMP for those times when I need to do something really complex and involved.  Which is maybe once every couple of months.

photoscope it is free