A few years ago I owned the DG (non-ART) version of this lens. I loved it on a D7000, as I could use the camera's AF fine-tuning to produce wonderful shots. However, when I moved primarily to FX and only had a D5100 for vacations, I wasn't as happy. Front-focusing issues plagued the lens and my shots, and I couldn't make the adjustments on the smaller camera. I ended up selling both the lens and camera.
When the ART version hit the market, I was very excited - until I saw the retail price. I couldn't justify the cost of the lens for what was essentially a travel camera (D5300). I began looking for one in the used market - and finally found one for a decent price.
Upon arrival, the first thing I noticed was the excellent build. I liked the finish much more than the older version. I also noticed that it balanced really well when attached to a D5300. It's quite a bit smaller and lighter (and MUCH less expensive) than the Sigma 35 1.4, so it would be perfect for travel - if it produced good photos.
At first glance, the photos seemed great. Sharp in the center, but softening a bit on the outer edges. I noticed the CA in high contrast shots, but that was expected, as my first version produced the same. I decided to do some pixel peeping, and noticed that there was a slight front-focusing issue with the lens. I suspected this might be the case, so I bought the Sigma USB dock. The program interface was simple to use, and after only two attempts, I managed to eliminate the focusing issue. The "Dirty Thirty" was back! I immediately sold my Nikon 35 1.8 lens and have been enjoying the Sigma ever since.
My conclusion is that if you can stay away from the outermost focusing points, this is a very capable lens that is a lot of fun to shoot. I would definitely recommend that you have the post-processing software to remove the CA (if you're picky about that).