I did the same thing this person is contemplating. I don't know I would advise it as a career move unless this person really likes starting over. As smoked said, this is the industry that has been exported to cheap labor markets and what have you. Challenges?? Well, building good relationships with board houses and board fab shops that will nurture/ tutor you in your infancy. Learn a good board schematic capture layout suite such as Protel DXP of Multisim/Ultiboard and study board layout strategy from some online sources and the engineers at your boardhouse. I wouldn't EVEN advocate doing this unless this person is very strong in basic electronic/ electrical design right now.
As regards embedded systems, remember this next statement. Expertise in Assembler, Basic, and C are really a must-have if you are going to produce anything much at all. If you were to settle on the Atmel AVR family you could use the AVR-Basic compiler for that and probably never need another language; but, that's a special case. I'd do it again even though itsmoked is right, I am just stubborn and what to do it ALL!!!
Circuit design and embedded systems are much easier to design today than 20 years ago because All the tools are so much more advanced and processors have more developed resources onboard so they come with functions I used to have to develop from scratch.
To ease into this, use one of the 3 new chips thats been developed that integrates Ladder Logic and basic intepreter as parralel sections of same controller. Here's one
Here's an easier one to grasp.
Each of these new products are to enable the plc programmer to buy a $30 chip and design a OEM controller; but, they allow you to tie I/O points to a independent Basic program as well. It's an entry point before you go entirely to Rabbit controllers with C langauge or an Atmel AVR with Basic.
Don't even start with Microchip, that's where I learned to cuss and spit, it is major crap to use the tools out there for that and nothing works as good as it sounds.
Pick an endeavor that is specific and stay with it until to are accomplished. Expect to work much harder for a year and you'll not be disapointed.
My 5 cents worth.