If you have the $350 go out and buy it, you can't get into the AR platform for any cheaper. Seeing as how you already have LARs and 5.56 there's absolutely no reason for you not to get it at that price.
also if you find out the AR platform isn't for you, you can probably sell it and get your money back pretty quick. That was my reasoning behind my first AR being a CQ-A, just over a year later, I've kept it. It's just that much fun to shoot.
If you decided to keep it, I'd suggest for the first little bit run it as stock, until you can sort out what you like and not like about it, then you can start spending money on it on the parts that personally bother you, I wouldn't go all out right away and replace the grip, stock, charging handle, hand guard, etc until you have a better idea of what's going to work best for you.
As for optics you have lots of options, I'm running a strikefire on mine which is decent and the price is right but I've been looking at the holosun offerings too, the one that has a solar panel really has my attention as you can run it without batteries, so buy the rifle now and then take your time with accessories those aren't going anywhere.