if your trying to save money and start off small, the jr is the way to go. you can always add extra modules down the road but those will cost ya. only thing that's really new about the A3 pro is that it comes with the level sensor and has a built in alarm. The Built in fmm is not really a big deal cause you can buy a new fmm module for about 100. That being said i ordered one anyway cause i like gadgets and the store excepted trade for the cost.
What i did find amusing was that they also have a 25yr anniversary limited edition a3 pro. with that one you get a sticker, a 25yr label, a hat and t-shirt and the most exciting additional feature is that you will get a hand signed thank you card. wtf?