I have a Garmin forerunner10. Whilst I get that it's not the top of the range gps watch, it only really has one job. And that's to find a satellite. I work in central London (City area) and it has never once found its location. It goes to power save several times before I give up trying. It usually works fine when running near my (fairly rural) home.
I've started taking my phone with me but it tends to weigh my leggings down. My phone gets its knickers in a twist occasionally and thinks that sometimes I run on water down the Thames but it's much closer than my damn forerunner. All its good for is a fairly ugly watch. Anyone have better success with anything else?