I often run disconnected in the front, It does handle different. I broke the bolt in my rear link. That was very noticeable with the front discoed. With the front connected i didn't notice the rear being broke but with both, holy crap.I have the stock bar, I had a broken link for a few months and never noticed it but after repairing it I noriced the difference. Without the front sway bar, there was a twitch getting set up to take a highway cutve at double the posted limit. Once fixed, the twitch disappeared, no need to set up, my Wrangler was just point and shoot.
I plan on installing the Currie AntiRock this year mostly so I can drop my winch 2". I know I'll have zero issues with reduced stiffness but yes, the TJ Wrangler is incredibly well balanced when left stock. I'm thinking a 4"lift has a far more negative affect on roll control than a smaller sway bar.