If you find yourself in I-net+ go for that. A+ and i-net+ are both of different exam and different job responsibility. I would say that the CIW design courses are an excellent supplement to someone who already tinkers with a bit of Web design stuff. I've done i-Net+. I-net+ and CIW both cover mostly the same stuff, but foundations has more questions about design and management with less protocols and IP addresses.
It's worth checking which version the trainer is offering. So guys, its totally upto you, what ever career you choose for yourself. A+ is meant for hardware and o/s technology exam, quite different from i-net+. But you have experience of site building and some of its tools, languages. I-net+ would be little easy for you.

Doing the CIW Webdesign Manager course at the moment. Although Im constantly leaning towards vastly better teaching methods such as video tutorials and the like so its hard to keep focused.