I have the BenQ on the radar as well ( the Benq GP1 in my case but should be the same as the Joybee though).
It seems to me that this category of mini projectors or portable projectors is pretty much standardized in terms of specs. Sure, each manufacturer emphasizes a different spec but in general all products are not too much apart.
The Benq got good reviews on many important tech sites. So, I am seriously considering to get one. Besides it has a couple of add-ons which I really like and which distinguish this pocket projector from other brands:
1. The docking station for ipod and iphone - that makes really sense, if ur a gadget freak you're likely to have one of them
2. the USB interface, you just plug in a stick and can right away navigate through the files on the stick. Navigation is done via the touch pad on the GP1.
3. 3LED technology for really bright pictures, screensize up to 80"
I'll see, guess the day is close when I go and get this one...