Thanks Mumblechum1 for the kind words, glad you can follow my instructions when you are painting.
I do rate Annie Sloan chalk paint and the issues people tend to have is through over thinking it. I know, I had to unlearn a few things to get to grips with the simple basic principle of no prep, stick to anything.
When they say no preparation, you should at least remove dust, blu tack and sellotape and scrape off big build ups of dirt and grease, if only to make the surface flat.
For consistent painting results, use a good 2.5" firm bristle synthetic brush and add a drop of water to the chalk paint, work thoroughly and steadily. It accommodates your painting style and skill level.
ie If you are a pro, you will be able to lay it on very fast and it will lay off nicely. I tend to do 2 coats for depth, but you can cover most surfaces in one good coat if you want.
If you are a DIY who would rather watch paint dry than apply chalk paint to a piece of furniture, it will also accommodate your less polished technique. If you have ridges, sand them out, if it doesnt cover, wait an hour and paint another coat on.
If it crazes, I can only assume you have lashed it on to a crazy thickness, or painted straight over some horrendous lumpy greasy surface.
Otherwise, I am not saying it is impossible to go wrong, but ...
For bleed through, go on my site and search bleed through chalk paint and it will tell you a solution (no pun intended). The hardest part is waxing, you need to keep it thin. There are a couple of basic tricks for long runs of work, with a bain marie and a sheepskin cover for an orbital sander, otherwise it is elbow grease and time.
Engineer heads should not use chalk paint, the arty side of it will do your head in. 