Eva, I have been using ACDSee for years now. Full disclosure: I worked for them for a couple of years too. i had been using PM 12 when it decided it didn't like Windows 7. Or maybe windows 7 didn't like PM 12..... Either way, it started running really really slowly, and hanging up on me.
I tried Bridge - UGH, Picasa, nope, then I liked Windows Live Photo Gallery, but I couldn't get it to "keep" my tags. I would tag things, then the next time I opened up the program, half of the tags would be gone.
I ended up caving and getting PM 14 and it runs real fast now.
I like that Its easy for me to organize things, I would tag my stuff say, 15-20 minutes a day. Its kind of fun to see what you have on your hard drive.
I love that is is flexible: For ex. I have a Main Category of Paper and sub-categories of Solid, Floral, Patterned, Notebook etc. But Anna's papers don't fit into those boxes neatly, so in one click, I added a new sub-cat of Artsy.
I use it mainly for digi-supplies and I'll Rate my favorite photos so I know which ones I want to scrap later.
You can view brushes and fonts which many of the other programs can't do.
it can get temperamental on occasion but I have to say I haven't had any issues with V 14.
The one BIG issue-- you can't move things outside od ACDSee or you will lose tags. At least it was always that way- no idea if that has changed...... but I tend to use it as my browser over using Windows libraries, so i haven't had too much trouble with that.
Hope that helps