I don't have a projector setup, so take this with a grain of salt. But I have done a fair amount of reading.
The Benq seems to be a great entry level projector for gaming, one of the few I have my selections narrowed down too. The Epson 8350 being the other. They are both very low input lag and put out a good picture.
The Sony VPL-HW55ES is several leagues above those projectors in quality, performance, and price. You should expect a much better picture, because you are paying for it. The input lag is higher on the Sony, but not anywhere close to what you would notice unless you are some kind of gaming god.
26ms is far lower than most TVs will give you, I wouldn't expect any issues. And in the TV world Sony is leading the pack in reducing input lag.
Is the Sony worth 3x the cost? It isn't to me, but it is a very well liked projector. I think you will be amazed with it. But if you want a lower cost option don't be afraid to check out the Benq or the Epson.