Not so Sure Signal
Mine allows me to make 15 minute plus phone calls, but there's a 25% chance it'll fall over when I terminate the call, and when it does fall over, I have to reboot the femto and my router.
Plus it does occasionally fall over for no apparent reason, maybe once a week. Once it managed to jam my 3G coverage, so I had to switch to 2G to get any signal. Oh, and it used to fall over as soon as I started uploading anything via my ADSL, but a firmware upgrade of my router seems to have cured that one.
Having said that it is sufficiently useful to justify its existence, my in house coverage has gone from maybe 1 bar to 5 bars most of the time.
Can't see how using femtos will fly in pubs and such like, not enough capacity, unless they make a 'super femto'; but then that's almost a Pico.