Hey, just tried the Maps feature. Very cool. I use Google Maps on a desktop frequently. Speed, with any layer on, is good. When I flipped on wikipedia layer, it showed me the exactly correct location of a church which was torn down about 60 years ago one street south of me. The Street view came up in a jiffy and rotates, etc, with good speed.
I run SpeedTest.net app from time-to-time to check the wifi. I am getting about 10 mbps download and close to 1 mbps upload with 30 ms ping time. I do better on the hardwired desktop, and better on a Samsung Tab 10.1 (about three times the cost of the Kobo Vox). But this is also a very consistent result for the Vox and may explain why the Maps app runs in a snappy fashion.