The GP1 gives a good clear image, mine has been used by a teenage Manga group in the local public library, and before they used an old bulb projector supplied by the library. They found the GP1 BETTER than the library projector - I was impressed !
This DP is good for use by environmental groups, or by anyone who wants a light portable DP for travelling. Because the lamp isn't a bulb it is probably a lot more robust, and can be moved when the DP is switched on or still hot, which is not safe for a DP with a normal lamp. The GP1 can be driven at 19 volts DC from a low voltage system, and it only uses about 50 watts. I use it with a bicycle-powered 12 volt system and a 12 to 19VDC adaptor. The only problem is that the GP1 power socket is not a standard size and I've been unable to source a rewirable power plug so I can fit it to my DC/DC adaptor.
BenQ seem only to have a small no. of standard replies to customer queries, all they will tell me is "your GP1 needs the benQ adaptor" , they won't tell me the size of the power socket/plug or respond to my suggestion that they market a DC/DC adaptor with the right power plug. I suspect their Customer Service dept. is computerised or manned by unskilled people who read from a prompt sheet, they don't actually know what I'm talking about.
In spite of this I'd recommend the projector. It can be operated safely from alternative power systems without breaking the warranty, but you'd have to use 2 adaptors if your power is low voltage: One to step up to mains voltage, then the benQ mains adaptor to step down to 19 volts DC
again - complicated and wasteful, each adaptor probably loses 10% of the power, not very helpful if one cyclist is trying to generate about 60 watts.... If anyone knows where I can get a benQ size power plug, can you please tell me ?