These first generation pico projectors are definitely not bright - all are less than 12 lumens in testing, although a couple we haven't gotten in yet, claim 15 lumens. (To keep perspective, the two we've tested that claim 10 lumens, measured 8.3 and 8.8 lumens. The lack of brightness is the primary weakness of these projectors.
Color accuracy and picture quality is probably the next biggest limitation. If you really want accurate color (or something closely resembling it), these projectors are not there yet. Yes, they are fine for casual viewing of photos, videos, or even movies, but, don't for a second, confuse them with the color handling of a traditional home theater projector, or for that matter, all but the worst of the business projectors.
On the plus side, they are the ultimate in portability. Several can do business presentations, either via VGA port, or an ability to convert (with software), various content like Powerpoint presentations or pdf files, into jpeg image files that can be shown.
I do like the pico projectors - I'm taking one on vacation in a week - Just for fun. I've decided on the Aiptek V10 Plus, because, I plan to download one, or maybe two movies onto it, and my daughter can view the photos and videos she takes in Manhattan, as we visit various neighborhoods. No doubt I'll blog later, on how it turned out. I had considered the 3M, because it will work fine with my MacBook Pro, but, since it lacks speakers, and a media player, it really isn't what is called for on our vacation.
Now that I've tried to give all you readers a decent perspective on pico projectors - their strengths and limitations, I suggest you consider this:
These projectors will get better, and brighter, and no doubt, less expensive over the next year or so. If you don't have a burning urge, or real need, I'd suggest you consider whether to wait 6 months to a year before plunking down the cash!
A last thought, discussed in more depth, on the Alternatives page. Long term, the real future of pico projectors - at least as I see it, will be those integrated into other portable devices. Oh, sure, lots of these stand alone pico projectors will be sold, but I do believe that the big numbers will be in terms of pico projector engines placed inside other devices.