To the OP, if (s)he is still listening: The option to have wider rims and tires is great on the new crop of go-fast bikes, and I think you'll find that they ride functionally identically, save for the braking modulation, etc. If you're a light and fast enough rider to notice a 200 gram difference in non-rotating weight on your bike, then you will form a more educated opinion on your first ride than you'll get from anyone here.

I was sold on discs on my first ride, but like Seattle Forrest, I live in a place with wet hills. And I am no lightweight. He and I also opted for the same new rims, which up the benefits to four:

• Wider tire/rim choices available (though the 2018 rim-brake Tarmac does accept tires up to 30mm wide, that's still not 32!)
• A wet weather braking system which does not have "prayer" as a required component
• Mountain riding descents where the worst-case scenario is "cooked a rotor and boiled my fluid" rather than "We're sorry to tell you this, ma'am, but it appears your spouse's wheel exploded on the descent"
• Buy rims once, discs and pads many times. Better than buying rims and pads many times. Great discs cost more than basic rims, but FAR less than great rims.

But basically your question is "Will I like them as much as the rim brake models?"

I think the answer is yes. I hope you'll report back when you find out.