Flaps3+10 when the QRH drives us to use Flaps3 due to weather, localized strong winds, LLWAS, Windshear, etc. Otherwise, Flaps Full is our standard. We'll see what happens when the A321s gets delivered in a couple of months.
FWIW - I always add the +10knots when using Flaps3. I've never seen it add much to the landing distance and find the energy doesn't "drop out" in the flare with the extra couple of knots to play with. Like any landing, it's all about managing your energy state and timing the deceleration/decrease in lift.
Your results may vary...
