Decide on your budget and get the best bike you can within your budget.
CF is Not fragile unless you regularly hit your frame with a sledgehammer. If you Ride your bike, it is fine.
Is it "better"? No way to evaluate. Better is irrational.
I prefer lighter bikes but I won and ride heavy bikes. And the difference of a couple pounds is pretty minor.
I'd look at the best groupset available (with Ultegra being my personal top end---Dura-Ace is little value for a lot more money, IMO) and DI2 being unimportant but something you will really like if you get it.
I'd say, strong, light wheels are more important than a 500-gram lighter frame. In my experience light wheels Feel faster, and well-built wheels are reliable.
If I were buying my Main bike, the one I planned to ride most of the time, I would spend every penny I could afford. It tends to break down to pennies a day in difference, for a reliable, fun and easy to ride piece of machinery that delivers every time. I wouldn't go for the diamond-encrusted bling bikes, but up to a few thousand, (or maybe more, I haven't been tracking new bike prices) you are probably getting value for your dollar.
For a back-up bike, I'd find a balance between economy and performance, simply because i don't need to have two awesome bikes with one that doesn't get ridden (in fact, I stopped buying or building bikes because I have too many awesome bikes and little time to ride.) For a back-up bike, to be ridden for variety, when the main bike is down for some reason, when the roads are sloppy ... save the $1000 and spend it on a commuter.
But foer a main ride, where you plan to spend a few hours at a time several times a month, don't even worry about frame material. Look at the build sheet.
Finally, if you are the type who would buy a bike with some trepidation, ride it a while, and determine that there is nothing to fear, then buy the lightest frame with the best components.
If you are the type who will be ruled by irrational fear and wince over every bump ... buy a metal bike.
After all, what matters (to me at least) is The Ride. if you enjoy the ride I don't care if you are riding a Mattel Big-Wheel. if you don't enjoy the ride, all the data from the ride---the average speed, the peak power, all that---is just trash.