I believe the ST2D016 was released in 2011, at 114 lumens. And if my memory serves me, Maglite upgraded the output to 134 lumens in 2012. So I believe the standard 2D LED is now 134 lumens, while the 2D Pro is at 274 lumens. I usually buy the 2D LEDs just once a year on Black Friday at Lowe's for about $15 USD.
The 2D Pro sounds good.