Similar experience here.
The first rMB I bought was an open-box unit for my woman, who's 11.6" MBA kicked a few months out of Applecare. She loved the rMB, but her compute needs are minimal (FaceBook, Web, MS Word). Eventually, I found myself "borrowing" her system, because it was so light and easy to carry around the house. I was mostly surfing or checking email with it, but it seemed to perform well.
Then I saw another open box unit, at Best Buy, with a steep discount. I bought it on a whim, because I was actually in the Market for a 13" rMBP. I fully expected to be returning it, which I didn't mind as it was open-box anyhow. Fast forward a month or so, and there's no way I'm ditching this thing. Aside from basic Web stuff, it tears through MS Office like nobody's business. It also does a fine job with all the iLife stuff. But MS Office is the most important for me, and I'd say it handily kicks the but of the mid 2013 13" MBA that my company issued me.
When I need to do power user stuff, I log into my 27 iMac. But for everything portable or on the road, the rMB does just fine. I'm actually surprised at how well it does.
Very much so ... I have the 1.2ghz 512GB SSD. It works great for me, I use it far more than any other machine in my possession right now, including the 15". It's my daily workhorse.