In addition to what has already been said, is price difference.
When the LG PA70G is on sale for 399, nice price. And for that price you don't ever have to worry about changing bulbs every 3,000 hours or 5,000 hours, because the life is 30,000 hours life. Also, let's not forget the 2 year warranty in the USA for the LGPA70G compared to the one year on the benq.
Also, what's not to like about being able to turn on and off the LED PJ anytime you want , whereas, every time you turn on a bulb based PJ, it puts a lot of strain of the bulb,and shortens the bulb life. With bulb based PJ, every time you turn it on it uses 4 hours of bulb life , or so they say, even if you only have it on 30 minutes.
With the LED PJ, it's just alike a hdtv. And I love that. Many times, I use the LED PJ to play game, then after 30 mins , if I suck at that gaming session, I turn the PJ off, and do something else.
I don't like 3D because it screws with my eyes.
If you are interested for just movies and gaming and don't mine having to change the bulb every 3,000-5,000 hours for 200 dollars a pop, go for the bulb based PJ.
Both are very good tech level stuff.