its suppose to be a test acknowledging an advanced understanding of general computers. I beleive that the ccna is pretty much the same thing, although what the ccna considers an advanced understanding is much more comprehensive. You can get a job as an IT guy with a+ certification, or maybe a job in a computer shop fixing computers, but if you have ccna your more likely to get a job as an IT, and will make more money because its a more prestigous and harder test.
I'm 17 years old, i have my a+ certification, and got a job as an IT in an office complex paying 15 dollars an hour. And i by no means am a computer genuis. In fact a lot of times i have to research problems, and if i cant figure out i come to computerforums.org and ask you guys :-D. I work 20 hours a week. If i worked a full 8 hour day for 5 days a week i would make $31,000 a year.
The guy who got me the job works two buildings down from me, and has 3 different kinds of certification. He has his a+ certification, ccna, and i cant remember the third, and he makes $65,000 a year working a 8 hour day 5 days a week. Thats twice as much, partially because he's older and is a full-time employee, but mainly because he has more certification. If i were you i would go for both.