mine arrived yesterday - charged it for 6 hours and it works like a charm.
its bigger than i expected, very heavy but totally silent until the alarm kicks in.
good thing is once its charged you can knock the power switch off and only use it when required ie for when the projector is used.
i have not tried it with the projector yet but it works very well with other sources.
i plugged my ps3 and dvd into it and switched the power off.
ps3 continued to work without a glitch and same with my dvd player.
i assume therefore that the projector would also continue to work without it being knocked off. there some comments that the UPS would have to be fast enough to switch to battery power for it to be effective.
for £25 its a bargain.
oh and the ps3 and dvd player both worked for at least 5 minutes before the alarm got on my nerves and i swtitched powwer back on so plenty of time to power down.