I've only been painting with the Annie Sloan Chalk Paints for the last 2 months, about 45 pieces of furniture. 

Lets start with - I LOVE LOVE LOVE this paint.  Previously my favorite paint waived between Ralph Lauren and Kelly Moore paints.  The Annie Sloan Chalk Paint has an even more wonderful smooth texture and depth of color.  It paints smoothly with a brush, paint pad, sponge brush, and roller. 

10 Facts regarding the Annie Sloan Chalk Paint:
1)  Smooth depth of color
2)  No primer is required, in most cases
3)  No sanding required for the paint to stick
4)  Dries in an hour, in most cases
5)  Paint is very forgiving, and touch ups can be added without re-painting an entire coat.
6)  Paint has a type of 'symbiotic' relationship with the wax. You don't have to use the wax but it 'seals' the finish and creates the great patina.
7)  For a different finish, the paint can be mixed with the wax creating a type of creamy finish.
8)  If you use the clear wax before the dark wax, and decide you have applied too much dark wax, you can remove the excess dark wax with a re-application of clear wax.
9)  If you accidentally leave the lid off the can, adding water to the paint will return it's great consistency.
10)  The Annie Sloan Chalk Paint wax also works great on other paint surfaces

Here are a few exceptions:
It is true that it dries within an hour - in most cases.  I have found that painting over antique finishes, wood finishes, and bare wood dries the fastest, smoothest, and truest to color.  So far, the exception to this has been old laminate finish & gold foil picture frames. 

Laminate finish - this exception is particular to pieces that are circa 50's and older.  It took about 3 hours for the first coat to dry, and when I started to touch up spots that showed through, it pulled off the first coat.  So I stepped back and let the piece dry thoroughly, painting the 2nd coat the next day. 

Gold Foil Frame - I wanted to paint this frame with the ASCP Paris Grey.  The paint went on smooth and started drying normally.  When I came back to the frame about 2 hours later, it had cracked up and away from the frame.  At first I thought it was due to it being a hot day, so I sanded it down and painted it again.  This time it was a cooler afternoon & I had the fan running.  The paint appeared to be fine, until an hour later and it was again cracked up and away from the frame.  I then sanded it down again, sprayed grey primer, and painted it with the ASCP Paris Grey.  This time it dried perfectly!

Primering - It is true that in most cases primering isn't required for the paint to stick.  However, I have found that the same paint rules apply for painting over white with a dark, or painting over a dark paint finish with a white.
I had a white cabinet that I wanted to paint ASCP Emperor's Silk (red).  Yes the paint went over the old paint perfectly, smoothly, and cleanly.  It dried pink.  Of course it did, any brand of red paint (except spray paint), painted directly over white would not be able to block the white and be a true red.  After 3 coats of red, applied over the original white, I still had a streaky pink/red finish. 
To fix this, I sanded down to a smooth base, primered grey, then painted with 1 coat of the ASCP red.  It turned out a beautiful red - exactly as desired.

In another situation, I wanted to paint a black cabinet ASCP Louis Blue.  I wanted to test out my primer theory, so I only painted one side panel directly with the ASCP Louis Blue.  Although the paint went on perfectly, it dried a greyer version of what I wanted.  I primered the rest of the cabinet white, then painted over with the ASCP Louis Blue - Perfect!