I picked up one of the new Haswell-based, 13-inch MacBook Pros with Retina display this past week; it's the mid-spec model with a 2.4GHz Core i5, 8GB of RAM and a 256GB SSD. I thought it'd be fair to give my early take on the laptop for those who are on the fence right now.
In short, this is what the Retina MBP was meant to be. The Iris graphics are clearly up to driving the 2560x1600 display, where the HD 4000 occasionally hit its limit with the past gen (based on what I've read from others). The PCIe-based SSD is very fast, of course. And the battery life is er, wow. Apple officially rates the runtime at 9 hours, but it's not hard to push that to 10 or beyond by lowering the brightness a small amount. That's wild for a system with such a great screen and a regular laptop processor.
Quirks? It's not a gaming machine, and neither the battery nor RAM are accessible. We really need high-capacity SSDs to drop in price, too. However, this new MBP strikes me as a very well-balanced portable. It's not going to make gamers forget something like the 14-inch Razer Blade, but it's definitely the laptop you want if you need an all-day system that still has some decent computing power under the hood.